Right? You don't have to join or even engage with Threads if you don't want to. Super easy to block an instance. But this brings a massive userbase and serious support to Mastodon. I'm a huge FOSS supporter and this is how the Fediverse not only survives, but thrives and grows - buy in from big players. Otherwise, when X/Twitter inevitably dies, another proprietary app takes its place. We just have to hold them accountable and educate users that there are Fedi apps outside Threads.