I've heard of this happening a LOT, and far too often: writers who got really positive comments from editors in critiques get a scant form rejection after many months and usually a status check. What gives? Are editors overly optimistic because it's hard to reject face to face? Are they encouraging a writer as a whole who they see has talent, even if that particular project isn't there yet? Or do they just want to get these people out of their hair, no matter what they end up saying?
It is certainly true that we're always more positive face-to-face than we are in our own heads. As has been recently highlighted on this blog, we're often very critical—even of the things we honestly think have promise.
If normal people could witness the weighing of positives and negatives, the calculations and arguments with ourselves that happen in an editor's head, many of you would start to wonder if we were, in fact, schizophrenic.
We aren't. But we are aware that what goes on in our heads is hardly material for social interaction. It has to be filtered.
And that's hard. How do we offer you enough of that mix of impressions and thoughts to be useful to you, without giving you so much that you're confused, or offended? It's also hard to be sure we're communicating what we think we're communicating when dealing with the wide variety of people we meet at conferences. I once answered a question that I could swear was "do you think my manuscript is publishable?" but that subsequent events proved the author had thought was "do you want to acquire my manuscript?" These are awfully different questions, obviously. Not everything that I think is salable is something I personally (or even my publishing company particularly) wants to produce.
All of that said, I still don't understand people who agree ahead of time to do something they (knowing the state of their desks and workloads) realistically cannot promise. (Though it should be noted that more than once I've arrived at a conference to discover I'd been committed to things I had not agreed to beforehand. Grr. I have a whole rant about pitch sessions that I'll save for some other time.)
So the answer to your questions are:
1. Some editors are fantastic editors, but are terrible at keeping their desks organized or getting back to people in a timely fashion.
2. Yes, sometimes.
3. Yes, sometimes.
4. Unusual. This reaction is saved for the rare absolute nutball who makes us uncomfortable / afraid they may be concealing weapons.