Okay, so i just talked about it with them. they said that they dont realy care that much themselves because they are convinced of its safetey, but that they are just worried about what others think about it. they said: "if someone sees you with it, they will think you are a addict and that you are smoking something else out of that thing"... ugh. i dont know
With the bolded part in there (that I added), I no longer see it as a 'their house, their rules' issue. With the bolded part in there, it is possible that if
they see you outside/anywhere doing it, the threat to kick you out could still be in effect, thus not really about doing it around the house, as logically you would be around less people.
I agree with what your parents are saying, but only up to a point. It is plausible that if others see you (and others that they know personally), those people may think you are an addict and/or are 'smoking' something else other than nicotine.
As you know your parents far better than us, and thus know best ways to approach them, and when, I'd just make a general suggestion that has you following their request to not do it around them while discussing and winning them over on their largest concern, how others will perceive what you are up to. I don't get why they wouldn't be saying the opposite, as in 'do it here, but nowhere else, unless you are in private residence with friends.' But as they are giving off a very confusing message, IMO, I think you just honor their request but keep poking away at it in way that you truly think works, given your knowledge of them. I'd also suggest stealth vaping at home, but only if you think it is truly stealth. Until you win on the larger point, then vaping at home is the smaller point and will just be seen as rocking the boat given their confusing position on this matter.
Also, to state the obvious, you could let them know that if you are ever allowed to vape at home, you would be considerate enough to not do it while
they have guests in the house or on the property.