It's a belief I find hugely depressing.
>reduces humanity back down to level of any other simpler life form. Eat, fuck, die, repeat.
It's a little more than that but though humans (most) are civilized and intelligent, we're still a great ape.
>It's a belief I find hugely depressing.
Why? It's our nature. Jonas Salk is probably the finest human I can think of and he was certainly motivated by all those things.
Just as a top-of-mind example: All through my adulthood, I really disliked Halloween. Just not my thing, too much pressure to pick a creative costume, then go to a tedious party. But last night I had such a great time taking my five-year-old trick-or-treating. Because it's so new and exciting and fun for her, and that's infectious! But that sort of thing happens a lot.
That's what the metaphorical "cake" is. But that doesn't mean "that's it, there is no other joy to seek in life now", like the parent comment seems to be inferring. It's just one source of joy, but one that is hard to capture any other way.
None of the rest of what you seem to have read into it is written there.