I struggle to see an issue with someone checking their phone whilst sitting still in non moving traffic.
It will be taking your attention away from the road, which means you might not notice as quickly when the traffic does move, and then you are unlikely to just instantly drop it as you start to move, if you are in the middle of whatever you were doing on it.
You should only ever be holding your phone if you have pulled over, right out of the traffic. The official interpretation I believe requires you to turn the engine off as well, but I don't think that should be necessary.
And that Mike’s guy is a total pillock
His aims are laudable, his methods less so. Though in this case, his method was just to video and report, which is absolutely what he should be doing.