That's not at all what I'm talking about.
There's a reason you can subscribe to commmunities you're interested in and block the ones you're not. It's so that you can curate your feed to reflect your personal interests which vary between individuals.
When it comes to what you're talking about; you're free to block threads.net instance yourself or you can choose an instance that does it for you. They're getting access to your your lemmy content either way.