Because we know everyone has their map up in the middle of a heated dogfight. 
I do, and when getting close to a field or a spawn point it's part of my overall SA .. trying to know where I am and keep every possible danger in mind. When theres combat close to a spawn point, there's usually a Gv battle too, which means tanks, jabos hunting tanks, wirbels defending the tanks or looking to get to a town. Spawn points are almost never "out there" but near bases.
But more important. What area are we talking about? How many furballs are truly ruined by magically appearing Wirbels? That is the point that is grossly exaggerated. There are only single points where wirbels can spawn, almost always close to bases.
The Wirbel effect on furballs (and that's what Anaxogaras is complaining about) is basically nil. You could also complain about field ack or CV ack interference on furballs.
I have been shot down by a Wirbel while being low & slow, I cursed the lame-azz-wirbel-dweeb for it (not on any game channel though

) but not even in my wildest dreams I would ever have thought to come to the BBS and demand any kind of action