Points 1&2- yeah custodians can rug you, this can happen with literally anything(yes with XMR)

Points 3&5- if you cheat, your channel peer gets compensation. If they cheat and you don't catch them for 2 WEEKS using a lightning wallet, watchtower, lightning node software, yes you got your money stolen. That seems reasonable because if you do catch them they risk node access, all of their channel funds, and reputation.

Point 4- yeah, don't let people use your computer and route over tor.

Yes, I conceded that if you try to steal your peer's funds, you DO lose your funds. My bad, I should have stated that caveat.