My best friend killed himself almost exactly a year and a half ago. We'd known each other through high school and he was one of the few people I would consider a true friend during those years. Sometimes we'd talk about suicide, since both of us were in a pretty bad place mentally at the time (although suicide was never a serious and prolonged consideration for me), but somehow I managed to pull through and then went off to uni. Trust me, in a headspace like that, you can't muster enthusiasm for anything other than perhaps recognising your own predicament in another person. Anyone who says suicide is "stupid" seems to always present an argument centered around "perspective," or "seeking help," but thats beside the point, when your mental condition is so contorted and prolonged to the point that it becomes all you know, any idea of escape from it just seems unfathomable.
Anyone who says suicide is "selfish," is presuming the sort of agency that comes with ordinary mental existence. I used to have panic attacks that came with the sort of terror and entrapment that made me instantly wish to be put down, it was unendurable. We aren't some sort of Tralfamadorians (Slaughterhouse 5 reference ftw) who exist outside time, and our perspective is situated directly in the moment.
I think it pathetic to pass judgement on something of which you have no personal understanding.