I don't see that it should be a turn off - I think it's nothing to do with not having enough confidence to go without, it's because it's an accessory. It's not shallow, insecure, any of that, at least most of the time. It's because it's the fashion, the same as someone wearing skinny jeans or whatever. Also, sometimes it's just because it can look very nice, and while too much is most certainly ugly and for sure there are some insecure people out there who hide behind it, you might not want to assume that they don't have confidence.
That said, I don't wear any makeup, I don't even know how to put most of it on, and people do look much better as their natural selves.
i have worse skin now than i did 10 years ago, which is saying something. Particularly with scarring. i don't wear make up to work because it's not really very practical with what i do. However, outside of that, if i can be bothered then i do put some tinted moisturiser on to try to mask it a bit; it does make me feel a bit more confident in myself.
If i'm not made up at all i feel like i'm practically invisible. In a weird anti-social sort of way i kind of like that. Invisibility does have its advantages. Also i prefer how my skin feels without make up!
On others i tend to prefer fresh-faced than the other extreme but if someone feels more confident wearing make up then all to the good, i know how that feels. Also love eyeliner on men :)