Pesachim 33a the gemara wants to learn from meielah to all other issurim, the gemara says that you cant because meielah is chayev for misasek and other issurim not.
But miasek is chayev by chilavim and arayos mikein sheneneh so any issur where you are nehenah you would be chayev for misasek
You perhaps forgot that the Sugya is currently learning Shabbos (where there is no Hana'ah, and not other Isurim where there is) from Me'ilah.
Nevertheless, the Tosfos ha'Rosh asks a question similar to yours. Since one is Chayav by any Mitzvah where there is Hana'ah, he asks, the Chumra of Mis'asek is a side Chumra, that has nothing to do with Me'ilah. So how can the Gemara refer to it as a Chumra of Me'ilah?
And he answers that since Me'ilah does possess this Chumra over Shabbos, we can learn Shabbos from it, despite the fact that it is a side Chumra, that does not stem directly from itself.
be'Virchas Kol Tuv
The gemara is clearly talking about all issurim, it just gives the example from shabbos, the pnei yehoshua asks my kasha I found but I don't understand his teretz.
We were told that this question is asked by (I think) the Pnei Yehoshua, who distinguishes between the Hana'ah of Chelev etc and that of Meilah (I think with Chelev, one has positive benefit from the fact that this item is Chelev, whereas with Meilah, the Hana'ah would have been identical if the item had been Chullin)
Meir Eliezer Bergman, Manchester UK
The Gemara is not talking about all Isurim. Initially, 'Sha'ar Mitzvos' referred to Cheilev ve'Dam, but now it is referring to Shabbos, as is clear from the Sugya.
The P'nei Yehoshua's question is why the Gemara learns from Shabbos declining to learn the opposite from Chalavin va'Arayos.
In fact, the Tos. ha'Rosh that I referred to appears to be asking the P'nei Yehoshua's question (though the Lashon that is quoted in his name is even now misleading). And he answers that in any event, since we find a Chumra by Me'ilah that does not exist by Shabbos (even though the same Chumra exists by Chalavim and Arayos as well), we cannot learn the P'tur of Meizid from Shabbos, and we still need "bi'Shegagah".
The answer, like the question, is unclear, and the question remains 'Why not learn the P'tur of Korban by Meizid from Chalavim va'Arayos (like the P'nei Yehoshua asks).
The S'fas Emes, who also poses the question, cites the P'nei Yehoshua, but refutes his answer, as he sees no difference between Mis'asek by Me'ilah (where the Hana'ah would have been identical had the item been Chulin) and Mis'asek by Chalavin va'Arayos (where the Hana'ah would likewise have been identical had the object been one of Heter).
The S'fas Emes himself, does not give a clear-cut answer, but the Chazon Ish does.
The Chazon Ish (as opposed to the Tos. ha'Rosh) maintains that the Chumra of Me'ilah is indeed unique, inasmuch as, unlike Chalavim va'Arayos, one is not Chayav for the personal Hana'ah, but for using Hekdesh, as otherwise, why would one be Chayav for using a hammer belonging to Hekdesh? Consequently, we cannot learn the P'tur Korban by Meizid, which is why we need "bi'Shegagah" by Me'ilah.
Be'Virchas Kol Tuv