Last weekend I helpd out at putt-for-mutts (a HOG ride for charity). I talked to a few younder Harley riders (late 30s or so) and they were all very nice ans didn't slam me or my bike. All had started on Japanese bikes and the only negative things I heard were they had bought bikes too powerful for their newer skills and they were lucky they didn't kill themselves.
These guys had nothing bad to say about any brand.
The only "negative" was when they heard I would be moving up to a Sportster next year, thay kept encouraging me to go straight to a Dyna. (Can't ever afford that.

I am hopefull that as time moves on, everyone will get a little more tolerant of other brands and less defensive. Or at least argue facts.