Commandments derived from the view

Hello Rabbi Michael,
You have often expressed that you believe that the sages do not have binding authority in matters of faith/view, but only in matters of Halacha.
However, there are quite a few commandments that are derived from a particular view on matters of faith. For example, reciting Kaddish for a son over his mother/father for only 11 months, according to the Ashkenazim, because 12 months is the length of time for the wicked to be punished in Gehenna (Rema Yoreh Deah, Siman Sha'av, Section 4, according to the Mishnah, Testimonies 2:10). I believe that there are several other such laws, and this was just an example, but if you accept the authority of the ruling to recite Kaddish for only 11 months, does that also necessarily mean that you accept the view behind this law?
I would love to read your opinion on the matter, or if you have addressed the issue, I would appreciate it if you could direct me.
Thank you very much.