In a capitalist society, people need money to survive. Capitalists want to hoard all the money for themselves while the poor do all the hard work for as little pay as possible. Unions aim to fix that problem.
There is no inherent contradiction between wanting a liveable wage for your work and criticizing capitalism at the same time.

I wasn’t bashing capitalism at all. My comment was directed at the fact that it is often (quite ridiculously) suggested that unionisation and its pursuit to protect workers rights and improve pay and conditions lead to the downfall of businesses. It’s an obvious weapon to try and disuade employees from joining a union by leading them to believe that they might lose their job completely when the union forces them out of business.

It’s pretty obvious that capitalism has its flaws but there is plenty of evidence to suggest that the alternatives usually don’t fair well. I don’t disagree with the ideology but I do believe that I am entitled to my fair share, after all, my bills are rising like everyone else’s. Why should my colleagues and I lose out so that a few at the top can fatten their pockets? They don’t pay me anymore than they need to - they compensate my colleagues and I sufficiently to make us do the job. If they pay less, I’ll look elsewhere and they know this by agreeing to the demands of my union.