There's a concept that אין עונשים מן הדין that appears a bunch of times throughout Shas (Makkos 5b for example). It basically means we don't learn out punishments the same way we learn out obligations. For example, the Torah forbids relations with a half sister (Leviticus 20:14), so kal vachomer a full sister. Therefore I'd say just like there's the death penalty with a half sister, there should be with a full sister. However, אין עונשים מן הדין, so there needs to be something more explicit to enact punishment (which there is, Leviticus 20:17). (FYI it seems to be a machlokes between the Rambam and Ramban if this is exclusive to kal vachomer or also other types of drashos. See Hasagos HaRamban to Sefer HaMitzvos Shoresh Sheni where the Ramban seems to understand the Rambam applying this rule to all drashos, and the Ramban says it's only kal vachomer)
My question is about the reasoning behind this idea. I assume there's some logic to it, and it's not simply a gezeiras hakasuv (although Mizrachi Vayikra 11:8 says it is), because I've heard explanations by the Maharsha (Sanhedrin 64b) and the Halichos Olam (Shaar 4 Klal 12). Halichos Olam says because one could err in their kal vachomers, the Maharsha says because who says the kaparah for one will help the other. I was wondering if there are any other reasons out there. Especially since it seems according to the Rambam it's not only kal vachomer.