Playing devil's advocate here...
Honestly, why not? What is so offensive about seeing a little vapor in a DMV line or courthouse hallway? If they cannot smell it and it's not causing them physical irritation or harm, what is the issue?
A lot of the behavior I see described as "rude vaping" is exactly that - rude vaping. Making a scene because an owner or manager asks you to stop is rude, not the vaping itself. Blowing clouds in someone's face is rude, but not typical vaping nearby. Blowing vapor in front of a movie screen is rude, because it distracts from the screen, like standing up or talking loudly in a movie. Using a pungent liquid that can be noticed by others and possibly make them gag from the smell is rude, but not vaping something that isn't noticeable.
Not all public vaping need be considered "rude" just because it can be seen. It's not the vaping that is rude or inconsiderate, it's the behavior of the vaper while vaping that is rude and inconsiderate.
(I basically agree with your post, just elaborating, lol.)
Your earlier post and this one have me wanting to ask is there any behavior in a public place, when spun a certain way, is not rude? Like, let's take standing still, being very quiet, and looking at no one in particular. Harmless and not rude right? But what if this person refuses to budge from that position? What if when asked a question, they choose to remain quiet?
I could go on with other behaviors, and purposely chose one that is I think the most tame one I can think of. But point is, everything done in public is plausibly rude in someone else's eyes. So, then comes the 'common sense' portion, but that has at least 2 points pertinent to this thread.
Common sense to vapers is that what we vape is not harmful, and not in itself rude to do. It truly seems to me in these discussions that some vapers think vaping in front of anyone is inherently rude. That is not common sense, but more like some sociological hangup for those who consider it to be inherently rude.
Second is, most of the people that hang around and care to discuss this, and are in favor of public vaping, aren't espousing to scream at top of your lungs if someone suggests to you on the scene to not vape in the establishment. In fact, we would either put our device away (begrudgingly) or attempt to educate, and exercise proactive common sense.
Common sense, right now, in today's political climate, when it comes to vaping is to do it where you can and to do it proudly. To do it stealthily or relegate one's self to only outdoor vaping is leading others, particularly non-vapers, to think it is something that is either shameful or hurtful to those in the vicinity of vaping.
Then beyond the rude portion is the political sense. Let's say all you who think not vaping in public is a good thing are faced with situation where now that 'we' managed to get that obnoxious vaping thing out of the public, how about we seek to ban it altogether in your local area? Perhaps that's going too far, but how can you disagree if you are one that says it ought to never be done in public? Perhaps on your internet vaping forum, you'll find people who shake their head and can't agree that a local ban is a good thing, but why should a non vaper go along with that position? If its rude/bad in public, regardless of the circumstances, then it is likely bad in private even if you can't bring yourself to admit to that.
The vapers who think that umpteen years from now the public will be more educated than they are now regarding vaping are living in a fairy tale, IMHO. If you aren't able to stand up right now and be bold to educate those around you, in public places, then what hope is there 10 years from now if vaping anywhere outside your home is not allowed? Are non vapers going to magically google search for education on vaping and take the time to explore all the items we have explored? And who will be their fair teachers on this subject? IOW, if ANTZ types get their way on public vaping, you think they'll stop right there and now decide a fair and balanced message can be taught, or instead will they go for more over the top rhetoric about the grave harm that comes from anyone who chooses to vape nicotine?