I don't think this is counter to what he was saying necessarily.

"I think that would go a long way as far as accident avoidance" Which according to you, means it could go a long way as far as 1/5th of car-bike collisions. I wouldn't say that is something to scoff at.

Now provided that the statistic is correct, yes that still leaves another 80% of the fault that needs to be addressed as a concern and people need to drive better.

But that doesn't mean we ignore the 20% (rounding here) that are also at fault on the cyclist side of things.

"but don't let facts get in the way of your prejudice" just seems like you want dismiss and excuse 20% of people who fuck up because another 80% are fucking up as well. We shouldn't give any of it a pass.