Because Apple fans understand something that you don't: the internet is the world's biggest echo chamber. You've got a number of factors affecting the problem's perceived size:
The number of people who genuinely have a problem (hard to quantify without access to Apple's figures)
The number of people who don't have a problem, but hate Apple (quite large)
The number of people who love Apple but hate Tim Cook for not being Steve Jobs (larger than group 2)
The number of people who don't have a problem, don't hate Apple, don't hate Tim Cook, but feel left out if they don't join in (I actually read a post from someone who said he didn't actually have a problem, but felt that he should because he read lots of other people were).
The number of articles repeating the same anecdotes from groups 1 through 5
Finally, the number of people who are using the service, don't have any issues, and so, quite rightly, don't say anything. (Size unknown).
The interesting thing that happened after the apology was the number of people now saying that the service is fine and Cook is a weakling for apologising! Damed if you do...
That's all very nice, but if, like me, you're actually in the group that has a genuine problem (a great maps app has been replaced with one that can't find anything in my area) that doesn't really help you.
I don't care if Apple's maps are 99% correct if I live in the 1% that isn't. Even more so because the service they booted was correct, and the features they're adding to the new maps app like turn by turn navigation are irrelevant to me.