You have to think on the physics here. You have static weight over the rear (if it's lowered, it'll have some rear bias). Then, you have momentum... weight transfer towards the rear during a launch.
Now, imagine a moment if you have a lowered car. That momentum can only be taken up so much before your shocks run out of compression caused by the springs keeping them in a slightly compressed state. If you can't fully transfer the vehicle weight properly, the end result is wheel hop and/or a side-to-side fishtail. Now, compare this to a monster truck with 3 feet of rear suspension travel. They punch it, you see the truck squat and it shoots off straight as an arrow. The suspension is converting linear energy to vertical motion and the majority of that energy is taken up via that energy transfer onto the rear suspension (directed straight down over the rear drive wheels). That is what plants the vehicle for a launch.
Granted, we don't need 2-3 feet of suspension travel. What we do need though is a responsive enough of a rear suspension to handle the weight transfer. A properly kitted out drag car will have a fairly stiff front suspension and a soft rear suspension with enough compression to absorb the shock of the launch, but with low enough rebound to prevent a wheel hop. Lowering springs will negatively impact the suspension's ability to launch as it keeps the shocks in a semi-compressed state, which torpedoes the rebound. It's more or less like installing a trampoline on the rear end.
I have not and likely never will ever install a set of lowering springs on a car I plan on racing (because they make the car slower). If I want a lowered look but want to retain full function of the suspension, I install coilovers. They're a lot more expensive than el cheapo lowering springs... but lowering springs are for show, coilovers are for go. Most coilovers are adjustable as well. This is great for dialing in the rear suspension if you need to make adjustments at the track or for just normal use.