It's an oldschool attitude to not touch things, from back in the day where software was so flaky that chances were someone had already 'exploited' the bug to do something non-malicious.
Ah, that actually makes sense, good analysis.
. It's pretty obvious from the description what the bug is, so saying you aren't going to fix it is, as you say, pure laziness.
This sort of thing worries me about glibc, and the attitude that 'bugs are no big deal' is a dangerous one that is infecting software developers all over.