It’s unclear if that was the reason of the suspension in the first place. I imagine only the admins know the real reasons.
But otherwise, as far as the mere mention/allusion to child abuse, shouldn’t a content warning suffice– and shouldn’t players decide for themselves whether they wish to engage with potentially triggering media?
I know in some countries, depicting children getting harmed in any way is illegal. I don’t know how many countries out there have such laws, but I wouldn’t be surprised if a lot of international marketplaces just prohibit such content, to be safe.
This is just my understanding of how this works, I do not know for a fact how any marketplace (including Itch.io) makes such decisions.