Maybe you don’t but plenty of people do. There’s a huge middle ground of people who aren’t aiming for “anonymous” and who aren’t doing professional opsec, but still expect not to have their pseudonymous online identities linked to their real-world-identity phone number.

OP is right, this is a privacy disaster.

Companies know that people think like this nowadays, so they only require the phone number after you are already invested into the service. Twitter had this where they would allow you to not set phone initially, but then ban you some time later and require it to lift the ban. Microsoft also bans you for “suspicious activity” and the only way to unlock account is to “verify” your number. You can only contact them about it via another ms account or… by phone. Fuck everything about this tbh.

For everyone to know, Instagram does this too in a way. They would let me sign up with just an email, verify it, then at first login auto ban me. Giving me the option of appealing and tracking said appeal by giving them a phone number.

The only way I could resolve it was by using a phone number. Meanwhile they've harvested 2-3 of my anon and temp emails.

I put a fake phone number into Twitter and a throwaway email. Got a few complaints about not having verified my number, then got banned for breaking the rules.

“Your account is permanently suspended After careful review, we determined your account broke the Twitter Rules. Your account is permanently in read-only mode, which means you can’t Tweet, Retweet, or Like content. You won’t be able to create new accounts. If you think we got this wrong, you can submit an appeal.”

I can’t even follow anyone, but at least I can read tweets.

As I tweeted nothing nor indeed followed anyone all I can assume is that you have to have a real phone number to sign up.