They are comparable to to the question "But if you want to live a happy life, why not inject yourself with heroin and feel super happy for a few hours? It would be the best way to live a happy life today."
Upholding personal rights, predictability and principles will maximise human happiness in the long term, while optimising for short-term happiness will often cause suffering in the long term.
Some examples:
> Say you’re a surgeon. You have 5 patients who need organ transplants, plus 1 healthy patient who is compatible with the other 5. Should you murder the healthy patient so you can distribute his organs, thus saving 5 lives?
A society where people are deathly afraid of sending loved ones to the hospital, for fear they might be killed and used for organ harvesting, will lead to the collapse of healthcare and cause far more suffering than temporarily increasing the supply of organs will prevent.
> You’re the sheriff in a town where people are upset about a recent crime. If no one is punished, there will be riots. You can’t find the real criminal. Should you frame an innocent person, causing him to be unjustly punished, thus preventing the greater harm that would be caused by the riots?
If this framing of the innocent is discovered, which is not unlikely, it will lead to complete distrust in law enforcement, and over time the corruption of law enforcement will cause far more suffering than stopping this specific riot will prevent. And the unjust punishment might cause riots for a different reason, anyway.
This might even match 1-to-1 with your intuition, if your intuition is "This seems logical on paper, but I don't want to live in a society where this happens, so I'm against it."
TL;DR: We live in a society.