ethanol in gas bad for our cars?

…says not a thing about adding 2-cycle oil (or any other variety of oil) to the gas tank of a car.
Hint: It has to do with vapor pressure. In any case I'll take that as a "no."
Unless and until you can come up with some kind of evidence to support your claim, that's all it is -- a claim.
I'm not claiming anything, just relating a bit of personal experience. Try it, you might like it. Or not, your choice. Just don't pretend you can read my mind or tell me how my car runs.

One last question, Dan: Just curious, is that you in your avatar?