The use of the term "oils" is not entirely inaccurate. I was discussing this a few weeks ago with a friend who is both a pharmacist and a food scientist. He wasn't at all familiar with vaping, so we discussed it at length (the baseball game we were watching sucked).
When I told him what was in ejuice, he seemed a bit fascinated. He couldn't think of any red flags concerning the sugar alcohols (PG and VG), and didn't seem concerned about flavors, either (although he did mention diacetyl--one of the bakeries that he does work for had to stop using it). But when I told him that all of the flavorings were water soluble and not oil based, he stopped me there.
He told me that almost all natural flavorings are derived from oils. Oils are the flavor carriers in almost everything we eat. The fact that the flavorings are water soluble is due to the fact that they are emulsified, usually with a polysorbate.
Apparently artificial flavorings are a whole other story...I got lost there...I never liked chemistry class.
Long story short, he couldn't think of any real issues related to vaping, although he was relieved to find out that I'm not using nicotine (I quit smoking a long time ago).
Of course, I never see ingredients lists for most flavorings, since the FDA only requires flavorings to be labeled as either "natural" or "artificial".
Aromatherapists have long used inhaled vaporized oils as therapy. They're not using ecigs to do it (at least not the one across the hall from my office), but inhaled vapor is inhaled vapor, and I'm not hearing of very many aromatherapy deaths.
So, yeah, a lot of y'all (me included) are inhaling vaporized emulsified oils. Doesn't seem to pose any significant health risk. Like my friend says "It's got to be better for you than smoking".