Yes I know that oral was not practiced a lot in the past within marriages in particular (though during the war in brothels I'm sure it was). But why do you think it's particularly kinky?
I agree in terms of deep throating, that's a bit of a kink and I personally don't like doing it (even as the one being deep throated). That was popularized by its namesake movie I think.
But normal oral how is that so kinky? I personally love it, it's a lot more gentle than regular sex. And it tastes so good 🤭 I even love doing that for hours (both ways) and skipping the penetration part altogether. 😋 But oral kinda feels like it's meant to be done.
It's not really a modern thing as such either. The kama sutra features a ton of it, including gay and lesbian versions.