Nothing of the sort. On Panic you can't exactly amass an army from the air. Griffin Conservatories and Dragon Fly Hives are quite rare. But for Necros with a guaranteed Transformer in the town, all conditions are right for them to breed and multiply.
Since when did it become possible to build a Transformer without a Fort? :)
It's worth noting that it's specifically on Jebus Cross that this Necro-grinding works the least
I agree there. But that still doesn't cancel out Jebus Cross's flawed design.
And about 700 skeletons - I'd like to see that. I hope you didn't start as Necro there? :)