That's the beauty of multiple instances. As long as people push heading to join-lemmy.org over any one particular instance, things should be mostly okay.
Yep, if they can find a smaller, specialised, or localised instance it is better for the network for them to join that and learn to subscribe to others rather than lumping on one big server.
It's just a little awkward for new users to subscribe and navigate across instances at the moment, but new features and "gasp" third party apps can make that easier.
There is https://lemmyverse.net/ as an alternative, I don't see any immediately shady communities in the top of the listing. Though it does put lemmy.ml as #1, which isn't ideal since it'd probably draw a lot of people right to it.