A good argument - but there is a lot of history here, and it's harder to get rid of history than anything else. The Chinese guy who invented the current iteration (there were one or two before and they also followed the same path) deliberately designed it to (a) replicate the effect of a cigarette, and (b) replicate the appearance of a cigarette. In addition, people converting to an ecig principally desire that it looks and feels like a cigarette.
So as well as the history, you've got the motivation of newcomers as well. This has a huge effect on marketing because the biggest market is far and away the new buyer. This is obvious because the largest ecig businesses of all sell almost exclusively to new buyers, not to the more sophisticated 2nd and 3rd-model buyers.
However your point is good, and in addition it has additional relevancy to the current survival issue that ecigs face, in a climate where there are powerful enemies with strong financial motivation to try and kill ecigs before their incomes are adversely affected. These groups are the pharmaceutical industry and their agents, the State and national tax authorities (and therefore government itself), and the
tobacco industry - which strangely seems to be the least problematic at the moment.
Those who initially named the devices a PV perhaps had the most foresight - but they have had the least success, as all the market forces are arrayed against them.
Ecig users are either still smokers or have quit, depending on your point of view. The arguments for either seem equally valid to me, but of course everyone's opinion is different and people are split between the two camps.
I tend to be influenced by the political fact that ecigs will either be banned as a pharmaceutical, or placed in the
tobacco camp as a consumer
tobacco product. Unfortunately neither the US or the UK will allow a whole new product area to be created that is neither a tobacco product nor a pharmaceutical and that will obviously take over the 'tobacco' market, which is one of the largest contributors to corporate and national incomes existing; and very few want to see ecigs classed as a pharmaceutical because that in effect means a ban. Because of the rigid nature of product classification, PVs must therefore be one or the other - a tobacco product or a pharmaceutical.
Of course, logically, they are neither - they are simply a consumer product like coffee. But there is no place for logic in government so we are forced to choose between two places we don't want to be anyway.
Eventually this will become a voting issues since 20% of the population smoke, and at least half of them will convert to ecigs, meaning that 10% of the population will be ecig users. That sounds like a percentage of voters large enough for politicians to have to take note of. Until then we are voiceless and powerless. The thing about ecig users are that they are strongly motivated and will probably vote on ecig-related issues before any other, and eventually politicians will have to take that into account. It's a few years down the line to that point, though.