As nice, as constructive, as encouraging as a rejection might be, it's still a rejection.
The agent's/magazine's/ezine's response is sitting in your inbox, waiting, waiting for you to click it open...and in that moment just before you click it, the chance is still there, the potential, the possibility...until you see the "Unfortunately" or the "I'm sorry to say..." or, as in one memorable case, the words "Dear: Lady" scrawled on a form letter.
I know rejections are part of being a writer. I get that, believe me. But still, on the days I get rejections I wish I had shells like Larry and Mrs. Larry. I wish I could pull myself inside and hunker down and wait until it was "safe" to come out. Although, I guess I do have my own version of that - it's called the couch, ice cream, and a Law & Order:SVU or CSI: marathon.
Of course, I eventually poke my head out, look around, and head back to my computer. I look over the query or the flash piece. I research other agents/magazines/ezines, and I send my work out again. And again. And again.