It's not just Facebook that causes neurochemical effects, it's every social media that people use compulsively. To be fair I don't doubt that they deliberately try to manipulate their users, but that's not something they have full control over.
Every single click you make on Facebook makes you a worse human being.
Come on. Really?
There is criticizing Meta as a company, for which there are plenty of reasons, and then there is fearmongering. If you think Meta is Satan I don't disagree, but hold back on judging the users for the sin of existing there. I don't think my aunt who used to send me good morning messages on Facebook is getting worse every click.
Those people are still welcome to join here.
Which is exactly why I want them to see us and know that we exist. Isn't it so bad for them to be on Meta? Lets show there are alternatives. Not everyone is keeping up with the Fediverse, and many people hear of Mastodon only to not understand it and forget about it. If they can see the Fediverse and realize that people have a better experience in it, they might finally make the jump.
As far as monopoly goes, that is a forgone conclusion. Federation or defederation, they immediately became the largest and most influential Twitter alternative. Once it gets on ActivityPub. it will be the largest instance. That's not something that can be stopped. Seems to me that by cutting ourselves off of it we are only isolating ourselves into a niche out of fear.