I thought the same until I tried and worked on the deck. Now they move with ease. I'm sure you have sprayed them with WD40 or something, take one hand and lift the deck a bit, almost jiggling it while you pull on the small handle attached to the clips. The weight of the deck keeps the tension too high to pull open the springs. I wear gloves to get a better grip when doing that.
The real "MF" is the belt tension spring. Comes off easy, getting it back on takes arm strength that my old back can't support. Always seems to take me 30 minutes and a lot of sweat and curse words. Good luck.
Oops, just saw a bunch of the same advice. Sorry, late night insomnia from back pains, didn't wait for the whole thread to pop up. All sage advice here, especially about lowering deck, putting it on concrete. I for one never have "giggled" while working on these God forsaken Cub Cadets. Will not own another.