Rabbi Yossi HaGlili reads the same verse about "what is to be eaten by all souls" and arrives at a different conclusion than Rabbi Yishmael. Where Yishmael excludes both animals and non-Jews from the festival food-preparation permission, Rabbi Yossi HaGlili includes animals — but not non-Jews.
His reasoning starts with the plain meaning of "all souls." The phrase naturally encompasses every living creature that possesses a soul, including domesticated animals. A farmer's obligation to feed his livestock does not pause on the festival. If anything, the Torah's concern for animal welfare — expressed elsewhere in commandments like the prohibition against muzzling an ox while it threshes — supports including beasts in "all souls."
But the verse also contains the word akh — "only" — which in rabbinic hermeneutics always signals a limitation. Something is being excluded. If "all souls" includes both animals and non-Jews, then akh must be cutting one of them out.
Rabbi Yossi HaGlili determines that akh excludes non-Jews while retaining animals. The differentiation is not arbitrary. A Jew bears direct responsibility for feeding his animals — they depend entirely on him for survival. The Torah elsewhere commands that a person must feed his animals before himself. Non-Jews, by contrast, are autonomous and capable of preparing their own food. The word "only" carves out the distinction between dependents you are obligated to sustain and independent persons you are not.