In theory, I don't mind them, but there are a couple of things they do that I do not like:
1. Talking over ride narration with a handheld camera. If you must film rides, do it without talking and use a camera harness that is close to your body. Keep the darned camera out of other guests' line of sight.
2. Film with narration in restaurants or pool areas. Take photos if you must, but keep me & mine out of them, and do your narration later when you edit them. And no, I will *not* change seats so you can get a better shot.
3. Film selfies while walking in the theme parks. Especially whilst walking backward. If you are walking, then keep your eyes on where you are going, not on your own face reflected in a screen.
The big crackdown that Disney parks are (very rightly) doing right now is banning phones being held on rides or carried in open pockets on rides. People are getting hurt when others lose their grip on their phone and it goes flying into someone else's body, not to mention the loading delays when phones are dropped under ride machinery. Put the phones away securely on rides: if your pockets don't zip or otherwise securely fasten shut, then put it on a lanyard down your shirt or use a strong wrist strap.