It’s still a social media platform, not every action taken is some nebulous part of Musks agenda. Odds are there was an influx of posts that qualify as spam from the signal.me domain that were marked by an automatic system as spam, because they were. Suggesting otherwise is baseless speculation.
Given that Musk has deliberately blocked links to whole other domains before for extremely petty reasons, I don't see why we should give him the benefit of the doubt.