I disagree. If you and I were having a discussion here and I made one of two alternative comments:
"Caveat, why don't you commit suicide?"
or
"Caveat, I don't know why you don't commit suicide."
what's the difference?
There is little difference in your example. But I think a more accurate comparison, in line with the original comments would be:
"I don't know how Caveat doesn't commit suicide"
vs
"Gonk suggested that Caveat commits suicide"
I think there is a difference and I think it matters.
But I should also say that I think Bertie's remarks were certainly insensitive and his response inappropriate.
I'm no supporter of Bertie by the way: personally I think he is a complacent chancer. But I reserve equal disdain for those who use semantic manipulation as a means of grandstanding and cheap political pointscoring, as Room305 suggested above.