I am not an altruist. My time is valuable, and while I will help people out from time to time, I do not feel that I have a moral obligation to, or that I should drop what I'm doing and lend a hand whenever asked. If the Roulette system didn't provide the rewards that it did, I probably wouldn't use it, or at least not nearly as much. That said, there's a difference between self-interest and being disrespectful towards others. Every run you turn down because they weren't in-progress is a group of players that need your help - that you implicitly AGREED to help by using the system provided, but then backed out on.

On top of all that, as folks have mentioned, allowing an "in-progress-only" option WOULDN'T WORK. All the tanks and healers jockeying for an easy run would pile into the "in-progress-only" slot, and none of those people would be available to help out a full run. With fewer tanks and healers willing to help out on full runs, far fewer full runs would happen, DD queue times would be nearly as terrible as before Roulette was introduced, and the tanks and healers that WERE willing to lend a hand on a full run would be unlikely to be prima-donna types that bail on a run (since those prima-donna types will just load into "in-progress-only"). All this adds up to "In-progress" folks sitting around in Roulette, waiting for the rare honestly disconnected player to free up a slot somewhere. While it's nice to have that resource available, I seriously doubt it's the instant-queue, fast win that folks are envisioning here.

The very existence of a display of the progress of the group that you're about to join is perplexing; it's hard to understand what value SE thought it was going to add to the game, and it's clear now this opportunity to cherry-pick should be removed.

You selected Roulette. You're being paid to help another group. Your entitlements end there.