The streamer was also suicidal, and responded to the viewer's note with his personal viewpoint on committing suicide. ("People who do it are selfish and weak" -- pretty much the same viewpoint we're discussing here.) Note that, since the streamer was alive, that viewpoint successfully prevented him, the streamer, from committing suicide.

For sharing his successful views, he was made a pariah.

Even if it did, the suicidal person themselves thinking suicide is selfish is a totally different thing than someone else saying it to them, especially in a moment of crisis.