I wonder in this wonderful age of litigation and risk aversion, if this is the tower staff not wishing to accept a non standard landing surface request in case they are liable for any problem.
If this is the case, they are probably hoping the pilot in command will issue a pan or whatever, and then they can be more helpful.
When a hellicopter asks for a takeoff clearence from somewhere that isnt the active runway (ie a movement area) in the US, ATC will append "at own risk" to the clearance. Why couldn't something similar be done here for non standard runway opps?