No involvement at all with the incident. I know nothing more than is in the report.
There are two separate aspects to the incident from the ATC perspective - the denial of clearance & 6,500ft, & what happened subsequently. The "C" controller who denied the clearance gave no level instruction & mentioned no other level to the pilot so any change in level is on the pilot or the other controller. Do you understand the differentiation? How does "clearance not available" indicate descend to 1,000ft? It could have been perfectly safely achieved by turning right 30 degrees for a few minutes.
Again I ask how is this any different to avoiding cloud?