To address only the "why would the recipient be affected by concrit" issue: in the comments that sparked this latest round of posts, there were a lot of instances of "why would you write character X as a bottom? That's totally stupid!" and the like, which...okay, the author only did it because the recipient asked for it.

If you were at a work gift exchange or a family gift exchange and somebody received...let's say a novelty t-shirt that you'd never wear in a million years, and the recipient said "Oh my God! Thank you! I never thought anybody would take my hint that I wanted this!"...would you say loudly "Damn, you have hideous taste and the person who bought it for you was just enabling you?" I doubt it. You might say that later to your friends, but probably not in that setting.

Or..you might. :)