Joseph: Because he’s a Ba’al Nefesh. Which comes with its own requirements and expectations. Hashem judges everyone on their own level.
Let me ask you a similar example: A Sefardi won’t use an Eruv (let’s say it’s Kasher for all Ashkenazi Chumros) because it has a street 16 Amos wide inside it. An Ashkenazi will. Does the Sefardi get more Schar? Do Ashkenazim get more Schar for all of our Chumros in Hilchos Shechitah? WIll HKBH take Schar away from Sefardim for eating Kitniyos? Why/why not? And how is this different?