Would people argue over the proper treatment for cancer as prescribed by physicians and oncologists?

Don't answer that.

Physicists who need a little help with the math become experimentalist. JK. (I was an experimental physicist.)

Physics is already open in a real way. It's just that the natural language of physics is math. And people don't like math, for whatever reason.

Re dismissing things out of hand: unfortunately, sometimes the errors are so obvious that all it takes is one look to see that it's wrong. I mean, if it's easy for a practicing musician to identify a chord by ear, why should one think a physicist is arrogant if they can spot the error right away?

(See my other comments here on arguing about conservation of energy and momentum in an online forum.)