Adding support for Kbin is definitely a priority. When I built that tool Kbin didn't have public defederation lists (yet?) though a pull request to implement that was in the works. Idk what's the status on that is, but as soon as it's merged I'll also add Kbin.

For any other software it's a little trickier. Unless there some way to check for this through ActivityPub of which I'm not aware, I have to go through software specific steps to scan those instances. This means that for Lemmy I go through an API that only exists on Lemmy, when I'll add Kbin I'll have to write some new code that will only write for Kbin and so on. This isn't really sustainable for EVERY fedi platform out there, I won't do that.

Moreover, as you saw there was a progress bar. That's your computer querying each one of those 300 instances looking for their defed lists. The more software I add, the more instances you as a user have to query, the longer it takes to run a search. All in all I don't think I'll add support for any other software aside from Kbin and possibly Mastodon.