UK Greens aren't NIMBYs. They're against doing more of what's being done across UK cities already - which is building generic boxy blocks of cheap housing that look like they fell out of Minecraft, and selling them for unreasonable prices.
Many of the flats end up in the hands of landlords, who charge even more unreasonable rents.
There is no sense in which that's a workable long-term solution to the housing problem.
The Green pitch is "That's clearly not working, let's not do more of it." Which has nothing in common with "We don't want anyone to build anything anywhere."
Mamdani wants to freeze rents of housing that is already under rent stabilization. He is also an advocate for reform and deregulation, and working backwards from outcomes. He has been talking to people from the construction industry and one of their main concerns is predictable time scales. He seems very pragmatic.
Talk vs action. The Australian Greens opposed Australia's build-to-rent legislation. They didn't oppose the entire legislation. They opposed the one part of the legislation that would have helped the problem.
Aside from the fact that the few policies they made explicit in their platform would actually be counter-productive to getting more supply (such as National-level rent freezes), they also don't have a good track record at the local level when it comes to housing.
I've been very involved in council-level politics where repeatedly the Greens members were aligning themselves with the right-wing members ("ratepayers rights"-type groups) when it came to delaying/blocking development permits, enforcing parking requirements, preventing/delaying rezoning, etc. They fundamentally don't understand the issue at all. All talk, no substance.
And that's before we get to the CFMEU matter, which I think was the final blow for them during the last election.
Explain?