It breaks startup for the vast majority of X installations for no
reason. It does not seem entirely unreasonable to describe a bug like
that as release critical.
I guess it would come down to who is classifying things as 'critical',
'normal', etc... Personally I think that that is just an annoyance,
you'd be misleading people into thinking that something awful would
happen if they didn't upgrade RIGHT NOW, making modem users tie up their
modem for 1/2 hour to fix something that they could fix with vi.