It's a worldwide phenomenon that motorcyclists in general wants to be open and inclusive. We wave to each other when we pass on the road, talk when we meet at gas stations and so on. But a Harley is not a motorcycle, it is a Harley. Most don't wave back, all frown if you try to talk to them if not out on your own Harley today but some Japanese bike and so on. Tesla and Apple users are very often in the same category of religious fanaticism for no good reason except brand loyalty. That is sad as one should be able to own a Harley, be part of a Harley crowd and not be religious about it but most (not all!) fall into this trap.
A tribe that is divided because of some businesses PR is always sad and harmful.
Secondary thing is that motorcycling is just a larger and looser consumer tribe than Harley or Yamaha or Ducati riders. Not quite as large as motorcycles + trikes, which is still smaller than bikes, trikes, and scooters. To some degree it is turtles all the way down in terms of how exclusive vs inclusive you want to be.
I personally don’t think there is anything inherently wrong with consumer tribes. The question is how does each one treat its members and newcomers and is it a healthy environment for everyone involved?
I'm guessing you are from the US, which I'm not, but I have never seen this in other bikers no matter the brand. Sure Ducati guys often hang out with eachother at a meet, as do other groups, but it's not like they don't greet other riders.
Heck, I even wave (end get waved at) when I drive my Alfa Romeo by both other Alfa drivers but also people in classic cars (and a few Ducati riders even). Totally different cultures than Harley riders, which I think is sad.
And before anyone calls this sad (which it might or might not be), consider that the alternative is either isolation by rejecting all forms of tribalism, or tribes formed around more harmful old school ideas (religious cults, violence-based tribes, tribes based on race/gender/etc.), or tribes we were born into and have no choice to leave because we can’t just buy the services of a farmer, a plumber, or a babysitter and have to rely exclusively on our tribe for those kinds of needs.