This is a common misconception. It's not that some men prefer giving pleasure rather than receiving it.
It's that some gay men get more pleasure out of giving than they do receiving. So by giving, you are basically receiving at the same time.
To me, the pleasure is all the feelings during sex.
If I orgasm, I have no interest in sex for a few hours. In the same space of time, I could bring a dozen men to orgasm through a gloryhole or a sex club. So the total time of pleasure is far greater giving than receiving.