And since I've had mine out and cleaned off the gunk... with just a slight pull straight towards the front of the car... it pops right out.

Yours have probably never been out... and just like a rusted on bolt on the bottom side of your car that's been there holding the apipe to the cat and would probably take an air hammer or welding torch to get off... it's probably fused in there pretty good. Be gentle but forceful...