Anyway, it's what I was told when I joined Google Ads a long time ago and it seems consistent with their philosophy and behavior.
So it sounds like their policy of having a high bar for proving identity but still publicising what is required to meet that bar works for preventing fraud?
If anything, your argument is an indictment against Google.
Trademark issues are therefore really simple: is the user of the trademark the one who has it registered or not?
But copyright holders don't have any standard, obvious evidence they can point to that shows it's really their copyright. They can file a DMCA, in which case companies normally just assume the complaint is accurate - but if the party on the other end objects, the case has to go to a judge who will determine who actually has the copyright and if infringement occurred.