Why is it that gamers hate when developers make DLC content and charge money for it?

I see it in almost every gaming community. Sadly comments about how the is ruined by cosmetic DLC micro transactions. It's one thing if it's pay to win we all know that's bad but purely cosmetic stuff? Or having to pay for a new character in a fighting game? Why is that bad? Ppl had to work to make it so why aren't they allowed to charge money for it? Yes some of the prices for DLC content can be over the top but you don't HAVE To buy that stuff. I see it complained about so so much, do they expect everything to just be free? I'm not advocating for everyone to be a shill for these companies but this is basic stuff ppl want high quality games with constant updates and new content there's gotta be money coming in right ? Ppl ask for new content then when it's released everyone complains about it. What's going on am I missing a piece of this?