You absolutely still need AC depending on the environment you live in. The most efficient multifamily housing isn’t enough to combat the hot and humid south or just insanely hot areas like the southwest.

While individualist capitalist ideology itself is a large part of the problem, most of those emissions are not from home AC. 69% of emissions in the US are from transportation, industrial use, and agriculture. The remaining 31% is “residential and commercial”, of which 18pp is electricity usage, of which residential AC would likely only be a small portion. Residential heating is likely higher since we still mostly use inefficient methods like gas and resistive rather than heat pumps (aka AC working in reverse).

And that’s not even mentioning the emissions we’ve offset to other countries for manufacturing. Something that definitionally does not include residential AC.

I would invite you to spend 30 minutes in the deep South during August and tell me that AC is a luxury, assuming you haven't already dropped dead from wet bulb conditions.

Shitty cardboard box homes are a major contributor to higher energy usage, yes, but that's not something the overwhelming majority of Americans have any control over even if they own their house. Residential AC still pales in comparison to energy usage by commercial real estate or industry, which contribute far more emissions and are much more relevant to tackle first for handling climate change.