Terms don't just have dictionary definitions, they also have political, historical, and emotional significance. The term "liberal" has a specific political meaning when applied to someone nominated for the US supreme court justice.
Basically, if you insist that "fair use" is a "liberal" cause, you are hostile to fair use rights because you are trying to associate them with the left wing of the Democratic party, which doesn't have the power to defend such rights.
If you care about "fair use", then it's important to ensure that everybody understands that fair use rights are as much a conservative as a liberal cause.
So, tell me, which is it? Are you trying to kill fair use rights? Or are you such a pedant that you insist on reciting dictionary definitions even if it hurts your cause?