Nothing has to be destroyed. Only removed.
They can do that however they want.
If private land is donated to the government, it's the government's responsibility to make sure that, as public land, it's for the whole public, not just the Christian public.
There is nothing sick or perverted about seeking equal treatment for all religious groups. If that means the Christians have to step down from their elevated position and join other religions, well, that's what it means.