What, you think the ATCO’s just refuse a clearance for fun? Just for a giggle?
They would have had a good reason to deny a clearance that day for a myriad of reasons and rules they work under and you know that.
This does NOT obsolve the PIC from using good judgement , airmanship and just plain good old common sense to keep his Aircraft, himself and his passengers legal and SAFE at all times. If he subsequently flew into a hill because he didn’t have a plan B that’s on him I’m afraid to say.