You're comparing apples and oranges there. There is nothing preventing you from filming or using your electronic devices (outside FAA regulations, and they're pretty clear when and when you cannot use the electronics, heck they don't even take your device away from you or deface it)

As much as I don't like the TSA, they're a lot better than venue security. Going on your anaology, if something happened in an airport past security, the airport isn't blocking your ability to call for help.

Bringing it back: What benefit is removing people's abilities to use phones and smart watches going to give you? (Yes, they remove both of those including fitbits)