Your problem is that you think that "art" automatically means "good art" or "deep art". You think that calling something art automatically makes it a compliment. No. There can exist shallow art, and there can exist bad art.
"Some films aren't art. Some music isn't art. Some books aren't art. Some plays aren't art. "
Sure, those few books and films that are designed without any thought whatsoever given to artistic criteria, aren't art.
But all music and all plays are art - I can't think of any example of such that's not designed with artistic criteria. Music indeed is probably the purest form of art there can be, and I doubt any example of it (even humming to oneself) can be considered non-art.
"Do you also believe that a pinball machine is art "
Yes. It's not *primarily* art (it's primarily a exercise for reflexes instead) and it's an extremely shallow kind of art (bright colors! loud sounds!), but to that limited extent it's still art.
"Heck, just as you claim that video games are art, some people also defend that football is art."
I don't see the rules of the game having been designed with artistic criteria in mind, so I'd disagree with that assessment.
Mascots and cheerleaders do perform art, however (comedy, dancing, etc).