Because its complicated, bumpstops arent a high dollar item, so why bother your tech support with idiots calling in wondering why a 4" long bumpstop hits their coils.... or COUNTLESS OTHER issues.
Anyone who has two brain cells to rub together, understands how bumpstops work, and can figure out how to work with what theyve got. The more info you give people, the more dumbass assumptions and stupid questions they send back at you... I really, REALLY dont blame them!
edit: Colorful language not directed at anyone in particular... beyond offroaders in general.