Death threats are never justified.
But I was paraphrasing Poettering's responses to perfectly valid criticism. He did basically say "fuck off", just sugar coated it, which doesn't make it any better. It's just really incongruous to hear someone who is so polarizing (on purpose!) claim that other people should not be so polarizing. And funny how he never seemed to notice these assholes until his friend, Kay Sievers, got called out on LKML for refusing to fix a bug he introduced. It fits though; Poettering is so short sighted that he can't even see the value in portability, nor does he think anything besides desktop Linux matters (when Linux runs, oh, everywhere).