Hmmm... I've never actually heard this story before. But it figures people would abuse it as a means to tell others to shut up...
Somehow reminds me of that whole 'first world problems' thing. Yes, sometimes it's literally about some stupid issue, but when you're talking about someone with severe mental health issues, serious financial problems, marriage breakdown and so on, saying "Well, people in 3rd world countries have it worse" is not really fair.
Why do people do that? "Well, someone else went through the same thing/had it worse, so why are you complaining?"
One doesn't negate the other, so why do people behave as though it does?
"It could be worse." is not a fair thing to say to someone who has difficulties in life.