I don't mind being told my front light is bright, in fact I'd rather know if I was blinding all and sundry, but I'd rather the person telling me didn't assume I was simply awkward. "Dim your light*," with the pantomime covering of the eyes, while not delivered with fury, would still have benefited from a 'please' tagged onto the end. And being alongside me as the admonishment was delivered in the Meadows means I had no chance to issue an apology and so look even more the bad guy.
Thing is, I've had that light mounted there (it's fixed in a specific point on my front rack with no option to move up or down) for months with no complaint, and tried to conduct tests myself on the luminosity, and so genuinely thought there was no eye-searing going on. I wasn't thoughtless in my light positioning, so would have appreciated just a little politeness.
If it was you, then I apologise for the position of my light, and will be moving it to a different point tonight so as not to repeat the feat tomorrow night; but equally, a little common courtesy goes a long way. Just saying.