I used to feel exactly this way and was surprised at some of the stuff. Dental office, someone in authority coming out from the back to saying you can't do that in here very firmly. People I know who get offended like its smoke ( old people) and I've never even considered it to be ok in a restaurant or grocery store. It's not so much about what should be ok but about making people uncomfortable, including myself if I'm honest so basically in public places I don't do it because I want a to have a pleasant day and usually that happens when I can make someone's day a little better or be left alone and not have someone be in my space about their weird world. To some people vaping is weird. Period.
I dont think people who vape openly in public have an an entitled attitude at all. What they do have is an enlightened one. Hiding vaping and being relegated to some dark, nasty smelly corner like a smoker is the surest way to get treated like one.
Regardless of the scientific evidence that the op calls for in this thread, it doesnt take a rocket scientist to figure out that vaping is a better alternative than smoking. If you can accept that (and I think most reasonable people without another agenda can) then you can see why there shouldnt be any association between the two.
I'll continue to vape openly and proudly wherever I damn well please since Im not doing anything wrong. The more people that see us vaping and that take the time to learn about it from a source other than the FDA the better off we all are.