Well, that's one way to quiet the crowd. While "the experts" may agree on this subject, it's also true that novice writers can learn quite a bit about writing through the helpful critique of more experienced writers. We get feedback all the time in the world of copywriting, and it makes us all better copywriters.
So, how about this... if you'd rather not have others critique your sputum, go ahead and spill the beans on your concept. It may be a horrible concept (save yourself some time), or it may need a little tweaking.
It's no skin off my back if users of this site don't want to post on the forum.... saves me gobs of time. It's up to you.