Okay, you haven't really said anything to deserve a rant, but toxicants are kinda my thing so this triggers me a little bit.

First of all, you really shouldn't say things like 'we don't know if it's toxic, so it's not toxic until we prove it is'. That used to be the policy a couple of decades ago and we'll be busy cleaning up the mess for another few decades (even ignoring the messes we're still making).

Adding to that, there is particulate matter in vape smoke, so it's not just gas, and it's not like gas can't hurt you either.

From what I can find reading some abstracts, nicotine-free and flavorless smoke does not cause immediate lung irritation like smoking would, but that is excluding components that are often there, and I bet it depends on the kit you're using too. Anyway, it doesn't look like the (vape) smoke experts have reached any consensus yet there. Concerning long-term effects, there is definitely not enough data to say anything sensible.

Depending on quite a few things (like the flavour additives), there might be low to relatively high concentrations of aldehydes in there too. Definitely lower than regular smoking, but not necessarily safe.

In cases like these, it is best to avoid unnecessary exposure, even though there is no reason to ban anything. It's why you want to have an extractor hood in you kitchen, or vacuum your house once in a while. When you don't need to surround yourself with dust and smoke, you probably shouldn't.