Too old, fat, physically disabled people, etc. can have a job and turn that job into petrol to feed their cars. OTOH they can't drive a bicycle. That's not very egalitarian.
The fediverse to which the most popular instances, such as mastodon.social, belong.
All the instances in the main fediverse have practically the same moderation rules and if you don't apply them to your instance they ban you and stop federating with you.