It might be. I remember that thread. What Adam didn't seem to know is that although ActivityPub and Activity Streams use a JSON-LD *data model*, they don't require JSON-LD *processing* (versus simple JSON processing). Mastodon, for most purposes, is doing simple JSON processing, which is compliant.

I self-host my Mastodon single-user instance. Setting up a few good relays can help with the isolation issue. I don’t notice it at all.