There's nothing "wrong" with a Dunlop D-402.... fine tire... but I doubt HD designed the bikes "around that tire"
more likey (as noted) Dunlop was the "low bidder" and they pay MOCO for the right to press Harley-Davidson onto each tire
Dunlop Elite-3 has MY vote, although I did like the grip/feel of the Metzler M880 marathons. Lots of other brands out there, Michelin, Pirelli, Contential etc...
Having the LOGO is important to some....... having white walls is inportant to some..... it's all about floating YOUR boat