I support unions. If I ever have the chance to organize one with future coworkers, I’ll do it. And I will always vote in favour of unionization, as well as actions beyond that, like strike action. We don't have enough unions nor strikes in Canada. Strikes also win, especially when the union is strong. Unions help workers fight back against employers, especially those who steal wages (inadequate raises, made-up nonsense wage penalties, etc.), implement wage/salary tiers, and fire workers unfairly. Unionized workers enjoy better pay and benefits in contrast to non-unionized workers.
Unions aren't a moral institution. They operate within the rules of capitalism. Not only does this economic system undergird much of society and its laws, but it demands competition, which by nature produces few winners and many losers. Under capitalism, companies and corporations compete against each other, but wealthier companies always outcompete poorer ones, who are absorbed or go bankrupt. This ultimately worsens the inequality and power disparity between the remaining workers and their much more powerful employers.
But the purpose of unions is not to overhaul the system they're forced to work within. Their purpose is economic: to fight for better wages and benefits for their workers. Of course, we form unions for moral reasons - to get what's fair and deserved out of the time and life we spend at work.
Employers panic when they find out their workers are trying to unionise. They'll start threatening workers with all sorts of things, often dressed up in friendly PR language to make it seem like they're on your side. This is union busting. It's difficult to list every single union busting strategy ever used, but a common one is employers claiming a business will fail or go bankrupt if workers in a workplace form a union. It's either a bluff or an admission that the business relies on severe exploitation to function. Never forget who makes decisions in a business and how it operates, especially when it comes to wages and salaries. If the business was struggling so much that its workers unionizing would cause it to fold, there wasn't much of a business to begin with anyway. Businesses like this are always unsustainable pet projects running on the labour of severely exploited workers. Such places are doomed to fail regardless of their workers unionizing.
Another point is that old unions, especially those during the Reagan to Clinton era from the 80s-90s, were (and some still are) big bureaucracies that often made concessions to employers. Employers may use this as a union-busting strategy. They would claim that union dues go toward feeding that bureaucratic nightmare. (I hate bureaucracies too.) The irony is that the bigger, and far more parasitic bureaucracy already exists in the workplace: the one created by the bosses. Out of every dollar you earn for the company through your work, how much of it is your boss taking from that? How much is their boss getting, if they exist? How about the shareholders? Out of the profits directed toward everyone but the workers, how much of that is being used to improve the workplace, give you better benefits, or simply distributed as raises?
Not to digress too much, but you should absolutely share wage and salary information with your coworkers. But more importantly, there should be wage transparency at the very top - everyone should know how much their boss makes.
Unfortunately, unions can become enforcers of their own. Agreements between unions and employers means the union also has to abide by the agreement, even if its against the interests of its own workers. If a union really has grown too big, inefficient, and employer-friendly to be useful to its members, then the workers should absolutely consider forming a new one. Your union must be accountable to you and your coworkers.
Indeed, some older, larger unions contribute to what's known as the "labour aristocracy". This is more likely to exist within unions because union contracts generally have higher wages and benefits. That's great! The problem is when well-paid workers fail to extend their winnings to lower paid or newer workers. Eventually, members of the same union could end up with large pay disparities. The result is tiered wage and benefit systems, which is a deliberate decision by bosses to increase the chances of workers fighting amongst each other, rather than against the boss.
One way to prevent this sort of in-fighting is militancy: going on strike. If a union doesn't strike, it's a guild. Worse, it's a social club. A union that's unable or unwilling to strike reduces it to a vanity project. It's why things like identity politics fail to achieve anything meaningful for the people it purpotedly helps. Again, the purpose of a union is economic, not moral. Its members, however, are free to take moral positions, which might mean breaking away from employer-friendly, union-enforced positions when the situation requires it.
Beyond unions, there are "worker centers", which operate independently. An example in No Shortcuts by Jane Macalevey was the North Carolina Smithfield fight, where worker centers played an important role in teaching workers English so they could engage their employer's lawyers more effectively. They aren't rivals to unions, but the existence of alternative organizations shows that there are other resources available to workers should a union be inadequate.
Of course, it's easy to write "I support unions". I've (unknowingly) attempted to organize a union once, but once was enough to learn that unions are one of the best and most accessible ways to improve the lives of workers in your workplace and beyond. After all, the workplace is where most of us are, no matter what identity groups we identity with or belong to. We give the best hours of the best days of the best years of our lives to employers, as economist Richard Wolff has said. It's worth improving your own situation, and the easiest way to go about doing that is to band together with your coworkers.
Mass unionization can help us win permanent universal benefits, like making paid breaks into law. Long ago, unions won us the 9-5; the 8-hour workday. For generations, it was an unspoken rule that you would get a lunch break while on the clock. Then, employers slowly stole another half hour of the day from us, because they insisted on the letter of the law. (Much of labour law was written to protect employers and the wealthy, at the expense of worker protections against employers.) A former employer I worked for took away the tacit paid breaks from my former coworkers and me. 8-hour workdays became 8.5-hour workdays for those of us who dared to eat - to survive. That single act of utter tyranny, callousness, and inhumanity taught me everything I needed to know about whose side I want to be on in what is and always has been a class war.
Get started here: https://workerorganizing.org/resources/organizing-guide/?amp#download
Unions: A Revolutionary Critique - Of particular interest here is the quote from Red and Black Notes. The rest of the piece elaborates on why unions actually have a mollifying, weakening effect on frustrated workers. In effect, unions actually prevent more strikes and maintain productivity / normal functioning of a business.