Yes. A four-wheeler will just go on straight ahead in a stable and predictable manner when I stop giving control input. But a two wheeler will quickly come off course when I lose visual feedback because it's a dynamic balance that requires continuous recalibration. It's a very good idea to signal that you are getting blinded.

These are very good points.

Eh, as someone who rides a road bike pretty often, this is par for the course for the "community"

We should be glad the kind of person who would go out of their way to endanger themselves and others with something as useless and petty as... retaliatory light flashing is on a bicycle instead of a 2 ton vehicle.

The people who give cyclists a bad name are never self-aware

I'm not trying to be petty, or throw a tantrum. I'm not talking a 10000s of lumens here. It's just the only sure fire way to educate the driver about the problem fast enough. It usually works out that we both stop shining lights in each others eyes, and and pass safer and wiser.