There’s a whole herd of elephants in this particular room:

• mods do what they do for ego. Sure there’s a few isolated exceptions in niche communities but in general they’re fief lords. As we’ve seen recently they will do anything to retain control of their fiefdoms, including backing down at the first glint of steel from their overlords.
• mods are easily replaceable by the army of 15 year olds waiting in line behind them eager for their own chance at being lord of the fief. Many current mods may actually have some skill and experience but that’s not essential. Think about your lawn mower guy - he’s been doing it for 100 years and does a fantastic job, but if he retired and his 15 year old son made a mess or your lawn, it wouldn’t be a big deal.
• unionising only works when you can’t legally just fire all the unionists, which is not the case here.