What you’re saying is probably close to the truth. Of course, most of us took the Daily Fail at face value - well, I did - that the victim was solely set upon because of his “sex change.” There could be a lot more to the story. But nothing excuses violence like this.
In other words, if this happened in Saudi Arabia, yeah the "they killed him because he was a transsexual" would seem pretty likely. In Brazil, less so.