“What does he have against Harley-Davidson that he hates those who ride their product?”
Triumph is a British motorcycle, unlike Harley-Davidson, which is made in the evil fascist corporatist AmeriKKKa!/sarcasm
As far as I know, Harley riders were anti-Japanese and maybe German. Triumphs and BSA's were always acceptable to the Harley crowd. He can't even get that one right (possibly the writer is unaware that the British were the good guys and the Japs and Nazi's were the bad guys back in WWII).