First of all, the act that was directly responsible for the persons suicide is him committing suicide. I find it hard to believe that the guy intended to push him to commit suicide. Yes, he tried to use his homosexuality to humiliate him but in no way can I see how that is a "hate crime".
What activity would that be? Just spying on a gay person is a hate crime? Pulling a horrible joke on a gay person is a hate crime but the same exact thing done to a non-protected class isn't? Or if a protected class commits suicide partly because of actions someone take is that a hate crime? What if those actions are technically legal, is it still a hate crime?
There are many actions that are technically legal but led to death/seriously injury/lost of property...etc, and the consequence many not be as severe as actions that was intended to do harm, but still you would be guilty for lesser crime. For example, voluntary manslaughter vs. involuntary manslaughter. You can be doing what's technically legal but resulted in death, you could face involuntary manslaughter charge.
It's not that hard, look at the case as you normally would and decide on guilt. If the case was initiated because of bias, be it race, gender, sexual orientation or any other bias, it becomes hate crime and whatever the guilt/punishment is handed out, it becomes more severe. Like this case, the action resulted in death, probably involuntary, and the action was initiated because of the victim's sexual orientation, it is a hate crime by every definition.