In my best computer speak -- this is JMHO FWIW.

The "Delta hates Comair" thing is overblown.
Delta hires Comair pilots. I've flown with some.

There is a relatively small group of senior Comair pilots who made some very mean spirited and offensive political decisions a few years ago. You all know what I'm talking about. If those guys were hired (or even interviewed) at Delta it would cause an uproar. They know who they are. I doubt they'd even bother to apply.

For the vast majority of Comair pilots --
If you want to fly at Delta, get your app in.