Users can report regular myTakes by clicking the grey flag icon (same as questions). The only myTakes users cannot report are promoted myTakes since they have already been approved by admins, which is why they were promoted. Regular myTakes have a grey lightbulb while promoted myTakes have a blue/pink lightbulb.
To be honest never knew a take could not be reported - As far as I know all takes by non editors are viewed before being featured and in theory editorships are only given to those trusted - I agree it is a dangerous process but I don't think admin has resources to check every take.
Well, I've never realized it was not possible to report a MyTake... I guess every post could potentially be offensive, nonsense, gramatically unreadable... And reading the explanation from the admin team I now realize this in indeed in the moderation manual. Though I must admit that apart from an occasional opinion I've rarely moderated MyTakes.
Honestly, i don't see how anyone can report a MyTake this was mentioned by another user that there should be a easier way to report ones that could fall in the category of violation or possible arguments on the Opinions, Comments etc.