I think the gist of what most people mean when they say " I' m entitled to my opinion..." , or " it' s a free country" , etc. is not to look down your nose at other people because they have a differing opinion than you or the next guy.
I don' t think this country is made up of a bunch of whiners, I think it' s made up of people who voice a different opinion and CAN without repercussions. That' s what makes this country great, and by saying " it' s a free country" means I can share my opinion whether it' s right or wrong.
I think this is a great country. I think having a different opinion is great. If everyone had to share the same opinion, life would be dull. Maybe more stable, but a dull life none-the-less. It peaks peoples thinking abilites to hear different views on things, and allows us all to progress more and more as a society.
Most of my opinions are probably wrong anyhow

, but by sharing my opinion, I can see peoples feedback and learn from it.
Probably most people put it as a disclaimer in their post so they don' t get bashed on just because they DO have a different opinion. Kind of " I' m tired of this mentality in these posts and here' s my disclaimer up front" .
To each his own and my two cents,
Thunder