If 80% of the USA wanted marijuana legalized, does that mean the 20% that say 'no' should keep it blocked?
There's been no ruling that Abortion is un-constitutional. The 80% has the full ability to elect representatives to pass a law on the matter at the state or federal level.
See, you're saying this, but with effective gerrymandering and friends, a collection of low-population states have successfully broken the democratic process by having a majority of power while being in the minority.
Then you should be in favor of abrogating decisions to the states and reducing federal power.
But as I described above, people in red states often have orders of magnitude more voting power.