User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-203.81.71.69-20140507062832/@comment-82.39.105.22-20141113104359

"Crowley was brave enough to try an negotiate with Dick, but didn't dare enter Lucifer's presence"

Which can be explained a few ways:

1. Crowley's belief that Lucy wanted to wipe out demons. As soon as Dick threatened to do the same, Crowley fled and started to work against him.

2. Crowley knew that Lucy could turn off his powers. He couldn't have known that Dick could do the same; which is now a reasonable assumption that we can make. If Levis can turn off Angel powers by sheer know how and age, it stands to reason that Demon powers are also vulnerable, seeing as how Demonic powers are essentially just powers granted by Lucy, if you think it through far back enough.

3.Dicks intentions being unclear, where as Lucy's intentions to rule everything were clear. No way to negotiate with the latter, some wiggle room with the former dependant on Dick's plans.