I don't think I've seen one at the top..
I'd say bottom because I'd rather not have the cord coming towards me, rather than away, when I'm using the phone. Also it seems more ergonomic for me to put my phone in my pocket with the top pointed down rather than up.
The question would probably come down to "valid criticism" vs "harassment". 1A does get into some thorny issues about when protected free speech crosses a line. I would expect that something that is objectively true (i.e. factual) would have more leeway than a subjective opinion.