It's not part of "democracy" in the strictest sense. Then again, neither you nor we have nor ever intended to have a system limited to nothing but "democracy."
One could accurately state that the concept of having rights that are not subject to the will of the majority is "un-democratic."
"Democracy," in the sense in which you're using it, is a vague generalization of several libraries worth of information, practices, procedures, legal and social concepts, and customs. All subject to interpretation or misinterpretation according to your opinions or biases.
Calling something "undemocratic" has about as much information value as calling it "unGodly." It's invocation of a magic word when you're too lazy to construct a solid argument.
We all know the general idea and it's not controversial.
We vote someone in with the intention to represent our best interests and their job is to represent our best interests.
We can bicker about what those interests are and if they've been properly represented and shit, it looks like we're doing just that.