The biggest reason this shit happens is because of how the worst of the left handles problem solving. This is less an issue with rank-and-file Dems, but it's a fucking huge problem with the progressives and establishment types (two parts of the Cabal, as
@Gehenna calls them).
They come up with a solution, then work backwards to force that solution, even if the solution is wrong or fundamentally flawed on a basic level. They will not listen to alternatives, even if those are better, will not meaningfully negotiate, will not heed warnings, and if (more often,
when) the solution fails, they will refuse to back off on it. They will then pass "band-aid" policies to prevent the original failure from becoming more of a failure, despite the fact that the original failure is still present. In this way, the problem metastasizes. It doesn't end until someone has the sense to pull the plug on the failed policy in the first place.