I will challenge the attitude of "should be wearing hi-vis" wherever I see it. It is not trolling, it is IMPORTANT that this attitude of "no hi-vis" as contributory negligence is challenged.
Should I be injured or worse due to the actions of someone else I don't want some idiotic judge saying "ah well, the driver was indeed careless but the cyclist wasn't wearing a little jellow jacket so must share some of the blame for the incident"
The more "AND he wasn't wearing hi-vis" is added to public perception to bulk up the list of "charges" against "what cyclists do", the more this influences the idea that a cyclist who isn't wearing a helmet or isn't wearing hi-vis must share culpability.
Challenge the wrongdoing by all means, but other things which are irrelevant should not be added to pad it out
Crankarm, you are indeed correct that the hi vis is an irrelevance. This is why I challenge the mention of it - it was not relevant to the wrogdoing and should never have been included in the OP (lights too are partly an irrelevance since whatever time of day or night, those bikes should not have been riding on the pavement.