Aaron,
When putting the igniter on it's harder to find the glow plug when it's mounted inverted, especially on cowled engines. There's often limited space between the glow plug and the ground, and when taking it off, you're reaching in between the spinning prop and the wing.

Why are youi giving him a hard time?

Now, the best bet for inverted engines is to buy a cheap foam cooler and make cut outs so you can sit the plane in it upright for starting. Of course, then you have to turn over the plane with the engine running.
Dennis-