Well...

I think that the reason Vazquez held back the fact that both victims were straight men was for a few reasons. First of all, it shows the reader that more than just homosexuals are targets of homophobic attacks. If people think that only homosexuals are attacked and hassled by homophobes, then it is less likely that they will stand up for the issue. By using this rhetorical device she is really taking advantage of the selfishness of people, who don't want that to happen to them. Second, she does this in order to grab your attention. The stories at the very beginning draw you in, but as soon as they end its easy to get bored. She adds in that information in order to make sure the reader is really paying attention. I think she waits to do this, to tell the readers that the men were straight, in order to shock the audience. It allows her to then argue her opinion with full attention, because not many people have probably heard of an attack like this.