The point is that the extent to which people's preferences are satisfied is just as objective a property of a situation as the amount of complexity present.

The preferences can be anything. If I claim that complexity should be one of the preferences, for me and for everyone, that's an objective claim - "objective" in the sense "claiming an objective value valid for all observers, rather than a subjective value that they can choose arbitrarily". It's practically religious. It's radically different from saying "people satisfy their preferences".

"The extent to which people's preferences are satisfied" is an objective property of a situation. But that has nothing to do with what I said; it's using a different meaning of the word "objective".

Trying for a sympathetic interpretation - I /think/ you must be talking about the preferences of a particular individual, or an average human - or something like that.

In general, preference-satisfaction is not specific - in the way that maximising complexity is (for some defined metric of complexity) - because the preferences could be any agent's preferences - and different agents can have wildly different preferences.