The police have more of a duty of care towards the members of public than rules and regulations associated with any religion or establishment.
Look at it this way, had the police been called if there was a possible breach of peace, or a physical threat, and the police took a moment or so to take their shoes off, and in that moment, someone got assaulted, or injured in some way, the police would be held accountable to some extent.
Second point, If that had been your mother, father, brother, sister or anyone linked to you personally who was at risk of being attacked, would you still be complaining that the police did not take their shoes off? And if you answer yes, then im afraid I beg to differ. Same as if there was a fire inside, would you expect the firebrigade to take their boots off? Come on, get real.
Im not saying that there was a threat of an assualt, nor am I saying anyone was being attacked, and also I do not know exactly what the police call details are, but what Im saying is, it seems to me that these guys are making a point out of nothing purely as they know the police have more powers than them at that point in time.
Third point, THE POLICE WERE NOT INSIDE THE MAIN GURDWARA! they were outside in the passage/hallway. If you want to complain about such petty things as such, then u might aswell bring up the issue of as to why there are shoes in the Gurdwara in the first place?... How about expecting people to leave them in their cars?!
Get real, these people who came in and are seen to be the main cause of this issue, have nothing else in their defence than to make a point out of the fact that the police were allowed in the hallway with shoes on by the secretary.