@Jain Sorry I missed this comment earlier. Thanks for the feedback.
- agreed that Mastodon's current behavior of just silently ignoring DMs isn't great, I should have mentioned that -- next time I do an edit pass I'll put that in.
I certainly didn't mean to imply that authorized fetch is made to supress others talking about something. Authorized fetch makes blocking more effective. You're right that there are still holes, and I should probably be clearer about that. But, incremental progress is useful. And instances may well decide they need to lock down and only federate with other locked-down instances, different approaches to social networks work for different people.
- agreed that admins could change the settings on follow requests -- although I believe it requires customizing code, so not an option for people using hosted installations (and a hassle for everybody else).