That's not true, because you surely can do that.
Ok, lets take my default Airport EDDP as example
Here we have the Gates 128, 130, 132, 134, 136 with Gateways
1 pic, a view to the eddp default gates
2 pic is in the gsx editor making the exclude file. ( here i miss the gate 134...why ever it is missing )
After compiling the scenerie excludes in the GSX Control Panel, the default Gates are still there , i dont know why.
I did it exactly like in the Video, just with the FSX because i did not have P3D installed at the moment.
Even after trying it with only gate 126 the default gate is still there.
also in pic 3 you can see, that every new sode gate is at the wrong position.
So even if it works with the excluding the gates, i must configure every gate.
So...no chance for one click editing