Okay, but what is achieved by ranting about it on the internet? Especially on a site like this. Heck, even shouting on the streets like a crazy person has more chance to change society than posting on Kiwi Farms.Taking the devil's advocate role and ignoring the coomer issue:
Slippery slope issues meets perfect storm of things that represent the failures of modern internet culture
In the past, there were boundaries and unofficial rules in place if you wanted to make money off of sex online. You NEVER used your real name for protective reasons and had to go through the Mindgeek machine or webcam sites, often making free videos/streams to build up a fanbase so that you could then force people to pay cash for the videos behind the paywalls Mindgeek allows or via personal website content that require subscriptions, etc. It was also a side hustle generally, and most people involved kept it on the downlow and you always look at it as a lark of sorts; something you did when you were young before you got married and then shove it into the closet of things you never talk about when you get older.
Onlyfans basically made it so that not only was it a "proper" career, but actively encourages people to use their real name; meaning that it's much harder to pull an erase everything deal once the novelty wears off and you realize you won't get rich and want to walk away and go back to your normal life like it never happened. Worse, Onlyfans has fed a notion that you can get rich off of the site in the wake of the pandemic, which isn't realistic all things considered given the glut of vanilla content on the website from amateurs and the fact that they are competing against people in the sex work industry with established fanbases also on the website.
Tossed into the equation is that Onlyfans represents a sort of gamechanger moment towards the issue of feminism and sex work, as far as the feminist idea that "my body=my choice" finally being put into practice relating to sex work. The feminist notion that women should be able to be sex workers since it's their body and they have every right to profit off of it, has never been put into practice to the degree that it has with Onlyfans. The ease to create Onlyfans pages, combined with a generation that grew up not knowing/caring about Rule One of the internet (NEVER USE YOUR REAL NAME), is resulting in a perfect storm of sorts where pro-sex work feminism is facing down the consequences of actually living in a society where anyone can be an online sex worker, without thinking about the consequences that would come about as a result of becoming an online sex worker in terms of the issues related to privacy and what happens when people find out about your side hustle.
In the past, you had to be tech savy to make money online as a sex worker. You also went into it covering your ass five ways to Sunday and there was an intentional level of disconnect between your fan/customer base and the person and the big money required networking. Onlyfans got rid of those safety rails and now you have to deal with the fact that a lot of people who didn't think about these things, dealing with the consequences of said safety rails not being in place.
TL;DR Onlyfans opens up a pandora's box of things that have consequences that no one gave a crap about until it was too late, combined with it being the culmination of a generation who grew up never knowing the rules of the internet to protect your privacy realizing why you never post anything online that can be linked to you.