Simulation isn't an addin, it's available with SolidWorks Premium. I suspect it has more to do with the fact that they're analysis tools versus design tools.
In my personal opinion the prerequisites for CSWE seems to be correct. There are not many people like myself who need to use the Simulation on a regular basis.
Simulation/Motion are specialised field similar to data management like EPDM and keeping them out of prerequisite section is acceptable and justified as far as I'm concerned.
I kind of agree with you. Simulation is not in my wheelhouse, but while I was studying for my CSWE, I was trying to pass it. My problem was my version of SW did not support it. I would have no objections to adding it as one of the prerequisites for CSWE. There are other features that might fit in also. IMO, if there were more in depth prof certs, it would allow someone to dial in and advertise their field of specialty.