Well, that's certainly one of the most reasoned arguments I've ever seen in my time here
I can kind of see the reason for the comparison, but it's obviously just wrong.
With Rita, the launch is the "setup" to the rest of the ride. The surge of adrenaline from the launch heightens the pretty short and lacklustre layout that follows. Without the launch, Rita is nothing.
However, the helix on Nemesis is part of the overall ride experience, not the major input into it. The helix improves Nemesis as part of the overall ride whole (and it's probably the highlight), but it's still a solid ride with out it.
In terms of forces, they feel completely different so you can't compare them. It's like apple-pie flour vs. cherry-pie cherries.