So queer I accidentally homophobed.

So I'm at work, and some group (all women) tells me that they need a guy for some task. I'm like "okay fine whatever" and I drop my tasks to go find a guy. I approach a random group of people, and I ask "okay which one of you is a guy" because like idk and EVERYBODY laughs. I pause like "...wtf.  what happened" before I realized that I was, accidentally, insulting the group by not assuming(?????).
It was horrible to witness and the original group of women did not end up getting help from a guy. :/