Everyone is different, we are all different. You cannot pull Taiji's mold on Yoshiki. Everyone deals with their pain and losses in a different way. (Pata drinks himself into alcoholism, Toshi allowed himself to be brainwashed because he couldn't deal with his own problems alone, hide was just as much an alcoholic as Pata, with body image issues, and I'm pretty sure Taiji wasn't an angel, either.)
Yoshiki chose to express his own pain in his music and on social media. He was not a very talkative person about his own life back in those days. Even his birthdate was long just known as X, along with his family name being written as X, too. I believe that Yoshiki is not only a very complex personality but he is seriously broken mentally. And that, my friend, is not a joke. He craves to be loved, that's why he posts about his pain and surgery and whatnot on Instagram and indulges in reading those hello-kitty-nurse-fans expressing their love and admiration.
I think he is a pretty lonely man, who has nothing else left just music and his fans. That's probably why he has all those milion sideprojects besides X, he HAS to work, he has to be in motion all the time, otherwise he would probably kill himself, being left alone. If you think about it, it is a pretty sad thing, to live a life like this. And with his personality, pride and being a Japanese male, he will not seek professional help.
X's music was born of the same method, that he chose to express his inner turmoil in music. Had he ever been a normal person, we would not have X Japan now. So loathing him for his personality basically means you trash the one thing that made X Japan what it is. The one thing that produced those songs you listen to. "Strong people just swallow it, stand up, swear and keep going, silently", yeah, had Yoshiki been strong enough to swallow his problems and just keep going silently, you wouldn't have these songs. NONE OF THEM would exist. You cannot separate a person's creative mind from his emotions and personality. If he were able to deal with his problems in other ways, there would be no need for him to make music.
And just to put things in perspective: Taiji wasn't able to deal with his own problems alone, either. Neither was hide able to subdue his alcholoism. And Pata needed a life-threating medical condition to cut back on alcohol, too. Toshi needed a serious kick in the butt to wake up. But Yoshiki's ways of dealing with his own problems are intertwined with his abilities to make music. Take away his problems, and there will be no music.