Yes, it seems unlikely this is deliberate. The SWP is about as likely to forment a revolution or incite violence as Judi Dench. They're a bunch of harmless eccentrics.
(Relevant context: the SWP is tiny and inconsequential, but very active in coordinating its [unlikely to be violent] messaging and inflating its importance. Nobody would know who its "dozens of leading activists" were to target them. And its local group pages are still up and easily discoverable by searching, so if it was a deliberate action to silence the party it would be a very sloppy one)
It doesn't matters.
You are as much responsible for decisions done by your algorithms as you are for decisions done by people.
If you can not guarantee that algorithms work in the parameters of moral and law you can not use them.
It is that simple.