A Uniparty discussion might be an interesting thread in and of itself.
From my perspective, the term is a very low-resolution descriptor of a mostly accurate concept. As such, it can be used to bring useful truths to a conversation, but someone fixated on the concept may at times become target-locked and take it absolutely literally - well beyond its usefulness and into the realm of falsehood.
It is somewhat akin to saying "men and women are equal." Taken at most levels that statement is true, but only up to a point. Someone obsessed with a literal interpretation would begin using the truthy parts of the phrase as cover for the parts that are categorically false using the typical motte and bailey strategy.
Are the Republican and Democrat parties similar in more ways than they are different? For sure. As it appears to apply here, neither is free of corruption, and both abuse their position for self-enrichment and to conjure up eye-watering amounts of money they can funnel to special interests, groups, and companies useful to them in a manner that is not conducive to a strong dollar.
However, taken to the extreme of "there are absolutely no differences between the two parties and it just doesn't matter who you vote for," it is more like the phrase "there are literally no differences between men and women."
I think the more black-pilled among us tend to routinely take the concept beyond what is defensible and accurate, and when challenged predictably retreat to their bailey and imply that their opposition must be denying the many legitimate similarities.
