If a city owns and operates a zoo, it's a non-profit entity by definition. If you build a zoo and charge admission, you pay taxes on your profits.
I'm not sure why this is so problematic.
It is a matter of market distortion that forces huge amounts of land into a very destructive control architecture. It places a large fraction of the housing stock in imminent risk. It impoverishes an entire industry. It enriches the wealthiest segment of the society at the expense of everyone else.
Other than that, no big deal