Reasons labels fail:
- Political labels mean different things to different people
- Language barriers create translation problems
- Political labels create a false sense of precision
- Labels change meaning over time and space
- Difficult to know how far apart two labels are
Reasons COLOR succeeds:
- Colors look generally the same to most people
- Colors come from (nearly) universal perception of the real world
- Everybody immediately knows COLORs are rough approximations
- COLORs are consistent over time and space
- Distances between COLORs are relatively clear
I'll apply COLORs to the word "Republican" as an example.
If "Republican" means someone who believes in a generally republican form of government...
Any COLOR could refer to a generally republican form of government, depending on all of the other characteristics of that republican form of government and the current form of government practiced in that society.
If "Republican" means someone who believes in a particular republican form of government...
An American who would like to return to a more originalist Constitutional Republic is probably YELLOW. The many Americans who believe that it would be better to empower other types of democratic republicanism as a way to limit the power of the Federal government might be classified as DENIM, AQUA, GREEN, YELLOW or ORANGE. There are also more consolidated forms of republican government that may be espoused by DENIM, BLUE, PURPLE, RED or ORANGE people.
If "Republican" means participation in the current Republican Party...
The core leadership of the Republican Party is somewhere in the PURPLE-RED area. People who vote for the Republican candidate in any given election could be any COLOR, but are more likely to be RED, ORANGE or YELLOW than BLUE, DENIM or AQUA.
If "Republican" means an activist in the pre-Civil War Republican Party...
A grassroots activist in the pre-Civil War Republican Party was most likely DENIM, AQUA or GREEN. The abolitionist movement and it's offshoots like the women's movement and civil rights movement are clearly tied across time and space to the modern far left to libertarian part of the spectrum. Northern REDs were generally active in the Republican Party leadership while southern REDs were active in the leadership of the Democratic Party.
If "Republican" means a member of the post-Civil War Republican Party...
An official in the post-Civil War Republican government was generally PURPLE. The consolidation of power going on after the war is consistent across time and space with the actions and ideologies of other groups that emerge victorious from a military conflict or maintain their power militarily.
The world "Republican" can mean any of these things. Treating the label as a useful marker between different times and places can lead to confusion. Using specific COLORs to describe the relationship between a particular republican and their society is more useful if the goal is to understand human behavior.