This is certainly a hate crime because same sex couples share equal liberties as tradition couples do. The responsible party reportedly said that "he would not put up with the couple living in his house." The person was obviously disturbed with having a gay couple live in what he though was his property. Discrimination against the victims based on there sexual orientation, and then physically attacking them should constitute hate crime charges.
A gay couple that had boiling water thrown on them was a crime of hatred. This is similar to someone attacked for their face or religious beliefs. The man who did it made anti-gay slurs while he was committing the heinous act. The person who did this should be tried under a hate crime.
Yes, the boiling water attack appears to be a crime of hatred. My main reason for this belief is that, according to an article in the Washington Post, the perpetrator yelled at the victims, "Get out of my house with all that gay." According to the police report, he did not deny what he had done to police and did not show any remorse for his actions. He threw the victims out of the house following the attack. The victims suffered severe second and third degree burns. They spent weeks in the hospital and will have a long road to recovery. This was a vicious, premeditated crime that seems to be rooted in homophobia.
Attacking with boiling water is a horrible crime. What is federally labeled as a hate crime is another thing. Proof has to be made that the attack was intentional because of race, sexual orientation, or religion. It is not always obvious and the lines get blurred because of this. Often, there has to be written records or oral statements to prove it was motivated by this.