> these same people would protest because it would “destroy the character of the neighborhood.”
It's not the same people. The bikes-and-trains people understand and accept that America's suburbs are not fit for purpose and would require radical redevelopment to be even remotely green[0]. They want to vaporize the zoning code to allow this to happen. The NIMBYs who are shouting about neighborhood character specifically want to keep their cars and lawns, and think all the environmental problems America has are someone else's fault.
People are suspect of quick-fix solutions because we've had decades of being sold quick-fix solutions (plastic recycling, clean coal, electric vehicles) when climate change and environmental damage are complicated, multivariate problems.
TBH I have been skeptical of degrowth's left-wing credentials. I'm not entirely sure how we retain democracy without unbounded economic growth when...
a) Human society has an unlimited capacity for elite propagation[1]
b) Elites will absolutely cannibalize the rest of us if further growth is not possible
[0] No, having a green lawn does not make your house green.
[1] Gestures vaguely at The Tyranny of Structurelessness