I think the problem is a bit more nuanced. Surely there's a jerk here and a lot of it is silly, but if Valve's changes stay and/or spread to other games they will have a big impact on PC gaming as a whole. I hate the whole #pcmasterrace jerking, but that doesn't mean that mods as they function today aren't a good feature for PC gamers.

Paid mods would change a lot of that, and there's other issues as well: the fact that modders get a relatively low cut, the possible shift in the modding community from people passionate about the game to people looking only to make money, copyright issues and abuses of the system, the high prices of some mods etc.

Now I'm obviously not saying that modders should be forced to make free mods, but that doesn't mean that getting paid mods to Steam is the best system for all sides (ie the gaming community and modders looking to make money). And while a lot of the criticism on reddit is just jerking, some of it isn't.

On the other hand, /r/circlebroke has a tendency to denounce any consumer complaints as "entitlement", especially when it comes to the games market. Again, in many cases that's true, but as a general rule consumers making demands from businesses isn't simply entitlement, and Valve is just another business. It's a two sided relationship and consumers should and do get to make demands and apply pressure on a business when its practices are harmful to said consumers, even if they aren't illegal. That doesn't mean that consumers are always right or should get their demands fulfilled, but simply expecting them to stay silent in the face of changes is ignoring the nature of the relationship between them and the business. Consumers and business aren't separate and independent, and signalling displeasure with business practices is a normal part of a market relation.

Consumer pressure has been applied successfully in other cases as well, and the gaming market should not be automatically excepted from this. But for it to even have some chance to succeed, you can't do it alone, since obviously a business is much more powerful than a single individual. You need to get people together and be firm in your position. This will necessarily imply some jerking, but it doesn't make it automatically wrong.