If Meta plays dirty, defederate them then. Now is just too premature.
These actors play nice until they are too big to ignore. If you let them gain that much ground, it's too late to isolate them without doing even more harm to your own network.
Also Meta is not a startup with unknown reputation. Meta plays dirty, that's a given.
The first step is a UX disaster: https://join-lemmy.org/
Only 2 clicks / pages down the road you can start registering an account, and you don't see what the experience might be before that. Instead, you're being presented tech talk about servers.
You might argue it's not actually lemmy but just the landing page. I argue, it's so good at being a scarecrow, most people visiting lemmy haven't seen anything else except for that page.
The inner lemmy is pretty fine, I agree. Some parts are still confusing. For example, most people will not figure out they can search for content from within a specific community by carefully configuring the drop downs in the general search form. Most will look for the search directly attached to the community.