Well, presuming the stoppage itself (i.e. the ref's indication that the fight is over) is uncontroversial, but as we all know they frequently are. Finishes are most often the result of ref intervention and waving the fight off (as opposed to the fighter losing consciousness or tapping), and this action itself is often subjective on the ref's part as he has to determine whether a fighter can still defend himself.
So, causing the opponent to go unconscious or making him tap prior to ref intervention is the only way to preempt any all arguing about the win, presuming the finishing technique is legal.
Right? But even then---you've got your Romero-Kennedy fights in which the ref stoppage appears totally justified, but the final result is STILL tainted because of prior events in the fight. Over this particular fight, peopled argue about whether Romero should have been counted out since he didn't get off his stool for another 15 seconds after the next round started (with further arguments concerning Kennedy's glove-hooking).
You're still right in the broad sense, because that small percentage of fights that end by KO/tap prior to ref intervention, and which also lack controversy regarding fouls and so forth, is the kind of fight we don't argue about. But it isn't uncommon to argue about a stoppage---I'd say at least every other card we get a fight that fits this bill.