Well, not all monkeys and apes live in areas where citrus fruit naturally occurs. But insofar as having the choice of consuming citrus peel, it seems they’re pretty enthusiastic. So I’m not sure monkeys/apes as a rule reject all citrus peel.
Apparently apes can eat the fruit, but save the peel for snacks later:
Elucidating the mechanism of “juice sac granular disorder” that occurs in citrus fruits due to high temperatures. We have pinpointed that excessive production of cell wall components due to heat leads to a decline in the fruit’s texture and quality, and we discovered the regulatory mechanisms of two genes that promote or suppress its function. Toward developing new varieties of delicious citrus even amid global warming. The Plant Cell