Because it's a liability and a pain in the butt. That's really it.
Especially since a lot of those are probably related to CSAM and other very morally unsavory things.
I'm not saying you can't determine what you want on your relay. I'm saying you're the only one who can determine what you want on your relay. Legal and moral liabilities are not yours to determine for someone else (at least not enforcibly).
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