Libs love suburbs too. Maybe they aren't quite as violently attached to lawns and detached housing, but they certainly love suburbs.

It's a lot of factors. Culture indoctrination is a big one. The cliche 1950/60s post-WWII "everyone is making it" type ideal (of course "everyone" excludes non-whites for the most part) is a mainstay for decades now.

On the more abstract level there's remnants of the American frontier and obsession by modern Americans (and not just today, but going back to like the 1940s and shit) of planting their flag on something and signing some documents to make it legally theirs forever. Anything goes in your little "castle" and you get to kill anyone who steps on your precious lawn... or so goes the mythology. They're LARPing, in essence, the idealized mythology of their forefathers.

Houses and more broadly speaking owning land (a few acres or whatever) was and still is for many people the ultimate goal. After the (now) Western US was conquered and brought into the US properly, there was no more land to conquer on the continent.

The entire mission of the US "manifest destiny" had been accomplished. The land was seized, the indigenous people killed or forcefully removed, and all the newly open land was divided up to the conquering people. Over time (actually similar to feudal Europe as Western Rome fell apart) the massive pieces of land got divided up as inheritance or sold off otherwise. If you ever look at how much land a single person or family once owned in like the 1700s or 1800s up into the 1900s it's almost laughable. Like one family owning modern San Francisco (real thing).

Anyway, all the absolutely ridiculous sums of land ended up basically into how it is today with all these 1 acre or whatever detached single family homes in the suburbs. It's getting smaller and smaller and smaller. It's kinda doing a multi layered thing if you're one to buy into the thought that owning land and having your little fiefdom is important. You still want it, but it's not as "easy" as it once was where you just joined the US army while they killed some indigenous people and then afterward you got a bunch of land. Or being the children, grandchildren or great grandchildren of those people. Now there's finite amounts of land, it's not "free" for people to claim, and that little dream of having your own little god-like palace is fading.

So, if you value that fantasy because you've lived 40, 50, 90 years or whatever of your life being told there is no other way, then it's scary to think it's ending. You have to covet what you might have even more. "Everything might be shit, but look at my beautiful two story suburban home on 2 acres that I painstakingly trim the grass on every 5-10 days- depending on the weather." It's always been there. It must always be there. And if you question it being there you are questioning existence itself in a very real way to them.