If you ask me, I believe men underwear are actually MORE dirty than women.
Guys don't really 'clean up' after peeing, most of them just shake it off then put it back into their underwear. Won't the excess urine that wasn't shake off properly transfer to the underwear?

True, I'm not saying all guys are like that.
My own bf (and all the guys in my family) wash off after going to the toilet. But I do know there are lots of guys who don't really bother either.
Sorry bro, I'm no bro la.
As above, I do know guys who clean up afterwards and I do know guys who make a mess out of the whole toilet. So it really depends on individual hygiene. My point was actually to point out to the posts above me saying what girls undergarment are 'dirty' and cannot wash together whereas guys one can dump into the machine all together.

Btw, are there bidets at urinals too?