All groups of road users contain groups or elements who are given to excessive or inappropriate illumination.
I find more among car drivers than any other group, but they do usually have more lights to play with: Failure to dip approaching oncoming traffic, unnecessary use of fog lights and the like in good visibility, holding cars on the footbrake on hills in heavy traffic.... there is quite a list.
Nonetheless, a small group of cyclists also seem oblivious to the effect their lights can have. I hear the argument "If I'm dazzling him, at least he's seen me". That seems not to add up as a justification. I'm not writing here about those cyclists who prefer to have multiple lamps front and rear; that seems eminently sensible. I mean the riders who, either deliberately or through ignorance, set their extremely powerful lights to dazzle oncoming motorists. In 'flash' mode, this would appear to help nobody. There may be an element of 'look at me!' about it. I suspect that most of the high-wattage, 'in-your-eyes' flashers are boys or men. That sounds wrong, but I won't edit it...
I suspect that in some cases these riders are not drivers, although that view doesn't account for the vast number of drivers who don't know where their dipswitch is.
These things are sent to try us....