Because they're assholes on principle.
These resolutions are toothless without the materials and logistics to implement them. Food should be a right and it's an easy thing to vocally support (unless you're manufacturing a famine in Gaza).
But how do you relieve the famine in Sudan if you're unwilling to export agricultural surplus at below market rates from Southern Europe? How do you meet global human demand for fresh produce if you're dedicating enormous qualities of arable land to high profit, low yield livestock? These generic statements of principle don't actually change how and why food is distributed.
And those are just the "capitalism bad" dumb lefty critiques.
What about in a war zone? Should we be feeding Russians occupying Ukraine? What about Israel settlers in the West Bank or Han Chinese in Xinjiang and Tibet or illegal Hamas ISIS Haitian Cartel MS-13 terrorists attacking people's dogs in Cleveland, Ohio?
Shouldn't we be killing these people instead?