It's not like ER cares for GC, it doesn't give a rat's behind about the stretch, ER just happens to be a fancy name for a division that should have aptly been
named "Kolkata railway division", and for stations within its jurisdiction, ER has its own way as far as halts are concerned, and its almost stereotypical modus operandi has always been skipping every station between HWH/SDAH and DHN
You don't even know the list of trains that used to skip stations like Durgapur in the late 90s, trust me it is...
more... much better now
However things are not so linear in the ECR territory, if ECR wants one of the ER trains to stop at its stations, it usually gets the halt in no time, and that does give one a false impression that ER is doing it out of the goodness of their heart but really, it is because their hands are tied, it's a Railway board thing