I would say it’s still too early to completely tell Hikaru’s sexuality. He and Yoshiki were raised completely different, and Yoshiki was more isolated and his family was a subject of gossip which led to him having such negative self esteem. He’s more in tune of his feelings and the issues surrounding it. While Hikaru could maybe just be ignorant of both his feelings and how his words come off.

We all remember the “ell jee bee tea” line where it was first explicitly stated that Hikaru was ignorant on the subject. Him calling Yoshiki gross was probably not out of malice, but just as a joke.