It's like they're trying to exorcise that demon within them that tells them they're complete phonies. Hell, Mickey Rourke even took up the sport.
If you are talking about boxing today, you are probably right. It's as phony as a $3 bill. But there was a time when the sport attracted men who were not only great physical specimens, but some of them had incredible mental ability, too. The turn of the century was boxing's greatest era. So if you are talking about the sport in general - and not just modern boxing - you are way off base.