I've seen comments on some of your blogpost/article things on your mains site, but no button to leave one myself.
Am I specifically blocked from it or something?
Nope! That's a byproduct of a feature on Activitypub, over on mastodon. If you comment on the activitypub posts, the blog incorporates that. If you want a mastodon instance to offer comments from, I recommend kind.social!
It's an interesting feature, and at the moment, less susceptible to drive-by comment spam the way the normal open comment feature was.