FWIW
I have used WD-40 for over a year on my razors with no ill effects to date...
I however don't spray it on the razor I use a small piece of TP then just wipe the blade. The only thing that I could see being bad is that it could cause skin irritation if you didn't wipe it off first....
Many of the police Dept's and the military discontinued use of WD-40 back in the 80's because there was a notion that it could penetrate a primer pocket on a round and cause a misfire from a dead primer. Whether this was ever proved I still don't know......