I really don't understand this.
There will always be people who have it worst than you do. Does that mean that nobody has the right to complain except the guy who has it the worst in the world ? I get that your situation was difficult, I really do, and I feel sorry for you but i don't think it is a reason to tell people they shouldn't complain.
Personally, I see that I am lucky enough to work, most of the time, in a warm office behind a computer and not outside, cleaning streets in the cold all day. But sometimes, my work sucks and I feel the need to complain. And it has nothing to do with others.
It isn't a competition anyway...