I think that most of the time, when someone says that another's work was less than perfect, they are really reassuring themselves out loud that they are doing OK. I think that we see so many beautiful things on this board, in magazines, and at guild meetings that we all have moments when we feel like we don't quite belong and that we are quilting imposters.
When I admire the beautiful quilts on the board, I can't see any mistakes and they look perfect and amazing to me. When I look at my own quilts, I can see every point that isn't perfect and I'm not amazed because I am too familiar with it. It's hard not to compare yourself sometimes - we all have those moments.
I don't think anyone of us would intentionally devalue the work someone put into a quilt - we know what goes into them.