Someone managing an exit node is effectively running an ISP - presumably in the USA they get protection under safe-harbour provisions like those of the DMCA (17 USC 512).
Aren't there also safe-harbour provisions for transmission of lewd/indecent content and for trademarks, libels and such?
Of course there being legitimacy of your actions in statute [if indeed that's the case] wouldn't mean you don't get hauled off to jail.