I mean out of the four concerts that I've been to in person, I can honestly say that I had no problems at all regarding cameras/phones affecting my sight or enjoyment. The loudness and hearing Myles Kennedy (when I saw him with Slash and Alter Bridge) talk in a helium voice in between songs was a problem (but that's another issue to talk about for another day) Then again, I was in the nosebleeds seats during those shows, so maybe there could be a difference in the GA section?
With that said, I'm 50/50 on the matter. Sure, I would rather see people enjoy the concert in real time as oppose to focusing on filming it or taking pictures/selfies during the concert. I do think phones/cameras could affect how involved and enthusiastic the crowd can be. I can imagine it would be really hard to clap hands in tune with the vocalist, get the fists in the air, headbang, etc if you got a phone in your hand.
That stated, if I hear word that someone's got a periscope stream of a band I like or I hear word that a band I like played this rare song from their catalog, I would certainly want to see footage of that and I mentally thank those that film it. It's a give and take, pros and cons sort of thing.
I can imagine guys like Corey Taylor and David Draiman would be miffed about it, since the songs of their respective bands are so energy driven that a crowd full of cell phones/camera users might kill the buzz of the concert. With that said, I wished they would approach these matters better as oppose to outright shaming and singling out a particular person and embarrassing them. Despite how people perceive them, Corey Taylor and David Draiman are a lot more articulate than what people give them credit for, but sometimes during their concerts, ego could get the best of a person and sometimes words/actions leads to negative buzz about them.