The reason the CDC is so concerned is because it's looking like vaping is undermining much of the work the US has done in previous years to decrease smoking in teens.
You're talking about vaping and smoking like it's the same thing, but I just take myself the freedom here and compare vaping to licking a lollipop or chewing gum, because there too nothing is combusted and therefore creating carcinogenic substances.
The nr. of vapers (and here in particular kids) who vape liquids WITH NICOTINE I admittedly don't know - it is therefore pointless to make a statement here, except that of course a kid which never smoked and started vaping has no "rational reason" to vape liquids with Nic, they don't need to "come down" from real cigarettes. They could as well vape just for the flavor. And I say: Why not?
The CDC can be and should be concerned once we have studies suggesting that vaping is indeed harmful. We DON'T have such studies, even if most studies conclude "we don't know" and it's POSSIBLE that vaping still has some negative effects which still have to be determined.
But what we DO KNOW is that smoking is harmful, and if I compare vaping and smoking right now I have any reason to assume that vaping (as an alternative to smoking) is "much better" with less negative health effects.
Anyone who is "for bans" is also promoting that millions of vapers who once smoked would be going back to smoking with all the negative effects.
When I found out about vaping about 10 years ago, I remember very well, at first I couldn't even believe that something like that even exists...I thought it was pure genius. I think I ordered my 1st ecig the same day when I learned about them. This was 10 years ago where people ordered stuff "from China" and really had no idea what they vaped. Now you have liquid vendors almost everywhere and many of them make liquids under strict and controlled tests and you know what it's in them.
For me, that vaping took off in the last years is a GOOD thing and not a negative. But I am not surprised that a multi-billion dollar industry (which vaping certainly has become) is demonized and I am pretty certain that the tobacco industry has their hands in there.