Night Flight,
Influx of experience and fresh faces helps with ensuring procedures are optimal. We all get attached to a set of procedures, and I'm sure there is also an element of discounting the fresh input as it may trigger change. This is common.
No procedure should be changed purely on a whim, so I would be surprised if pilots joining your company are given free reign to make changes. They may offer feedback via the appropriate channels and then that feedback should be considered on merit.
Any proposed changes should be accompanied by a convincing argument as to why it would improve the operation. If this is the case, then it's likely the existing flight crew are resistant to change. SOPs are just SOPs. They don't define us and we shouldn't become defensive of them.