At that rate you wouldn't count Mastodon as apart of it ActivityPub either was Mastodon didn't originally use it ActivityPub. The only other reason you can say it's a bridge is because you have to turn on 'Fediverse Sharing' to enable it.

It was built as an extension to it, it wasn’t the main intent behind it. The activitypub is extremely limited anyways and unavailable in eu.