Piefed.co.za is less than a day old and likely has done no federation at all yet.

That cannot be true. I can see a bunch of communities federated on that website. For example, search for ‘news’: piefed.co.za/communities?search=news&language_id=…

In it, he excluded federation from communities with certain keywords that you have already bought up.

Okay. I call that a hardcoded block (that can be manually worked around).