"Equity Red Star compared car drivers to car users who also have an insured motorcycle, and found the latter 23% less likely on average to make a claim on their car policy."
Dunno about you, but the way I interpreted that was those who also have a motorcycle and more likely to be hooning around on it and leaving their car parked up back at home... Unless the stats have been normalised for all multi-vehicle owner, multi-car or car+bike(s), it's not particularly conclusive.
"The results showed motorcyclists were 20% less likely to make a bodily injury claim on their car policy."
Oh come on, in an incident with a bike, we all know the biker comes out worst and would typically claim against the other party. It's super unlikely a bike would injure the driver of a car, in fact the few times a biker does cause injury will probably be against pedestrians or cyclists, and these naturally will count for a small fraction of all incidents involving motorcyclists.
All in all, we have a bunch of random stats that have been massaged to produce some nice catchy headlines.
However, I do actually agree with the sentiments that an experienced biker will likely be a better driver as well. We've been through two tests for a start, and we're very used to reading the road ahead well and good at predicting what other idiots on the road are going to do. A lot of bikers also have a strong urge to self improve and be better on the road - a rare trait in car/van drivers.