I don't remember what I ate last night
but I can spout off obscure rules to all sorts of games like nobody's business!
The Monkey See Adventure card says to lose half (rounded down) of the roof level OR palisade level. Can you choose something with a level of 0 if the other is not 0? The rules state that you can choose a level of 1 to lose nothing but can you choose a level 0 palisade to lose 1 health when your roof is level 2? The rules state that if both are at 0 then unfulfilled demand applies but it isn't clear on if you still have a choice if one is 0 and one isn't.
In this case I would have much preferred losing 1 health for having no palisade than losing a roof level when I would be rolling a weather die later.
I played it as I had to lose the roof level (level 2 to level 1) which cost me a more than 1 health when I rolled double clouds (unfulfilled demand on the cloud and then 2 health for not eating).
You played it correctly. You cannot voluntarily choose to trigger unfulfilled demand when another given option is available.