It is true.
But, everyone who talks about it, makes it means different things.
Another thing about having a higher IQ is that you tend to want a relationship. The lower IQ tend to want sex. The higher IQ comprehend that there are risks. The lower IQ doesn't have the mental processing to let it bother them.
It is similar to the misnomer about going to college means you will earn more. When, it is just that those who can go to college are of higher IQ, and so, will earn more money (if they choose to do the mentally harder jobs, which tend to pay more.)
And, we should not forget that if we didn't subsidize single-motherhood (section 8, SNAP…) then most women would not go to bed with not so smart guys.
Its a whole string of dominoes.
I love this. It seems so obvious now that you point it out but I never thought about it this way and this is absolutely true. I now recall how a ton of people who I perceived as being low IQ started college, but a lot of them didn't finish.