Someone who shares an opinion that doesn't match with yours, doesn't have anything to do with their lack of maturity. It's just their opinion.
Also, saying that people can't comment on something unless they've experienced it themselves is just silly. I've never done Heroin, gone drink-driving or shot someone. I can still have a negative opinion of them.
I've lost 22 pounds in 10 weeks to prepare for my upcoming trip, and still want to lose another 15 pounds before October. That doesn't make me more entitled to an opinion on weight loss than anybody else on these boards.
My opinion is that there is no such thing as being 'big boned', and I have no time for people who say "It's my genetics!!". The simple truth is that if you consume less calories than you burn each day, you WILL lose weight. You cannot cheat science, only yourself. This is the advice that every doctor and dietician in the world seems to offer, and I am in agreement with them.
That's my opinion anyway