It's not just the left that support Roe v Wade. Unwanted children are thought to have been a factor in the high crime rates of the past. Most crime studies I have read state that legalized abortion was one of the factors in the lower crime rates in the decades after Roe v Wade. If you accept the concept of Stare Decisis,
https://www.law.cornell.edu/wex/stare_decisis the law is decided and a three month old fetus does not have the protection given to a human being.
It's a woman's body and she should have a reasonable choice in what happens to it. I doubt the majority of people want to provide support for unwanted children or suffer the consequences of these people growing up, so I don't see it ever changing.
It is in keeping with the culture of this country. We are a pro death nation. Pro choice, pro gun, pro death penalty.
That is the US that I know. You may not like parts of it, but at least we are consistent.