Democracy is set up on the idea that what the majority wants must be right. This disregards the legitimacy of the voices and concerns of minorities, and puts too much power into the hands of those who are already privileged. And more often than not, what the majority wants is detrimental if not outright harmful to minorities.
Politicians are well aware of this dynamic, and they actively exploit it. They spend endless hours and resources campaigning to the majority voters, because they know that winning over the majority means winning elections. This means that they listen to and hear only the voices of the privileged elite; of those who are like them. Minority voters are then overlooked, ignored, or even blocked from voting.
Their voices are rarely if ever heard, and their needs and concerns are put on the back burner in favor of catering to the wants and whims of the majority.
And what the majority wants isn't always right or good. There have been many court cases where an innocent person was found guilty because of a majority vote.
The majority of white southerners during the American Civil War fought to own slaves, even if they didn't own any themselves, because it was in their own self-interest to keep slavery legal.
Theirs was the majority vote because slaves weren't even allowed to vote; their voices were silenced. But what the majority wanted wasn't right nor humane. Thankfully, they lost the war; but just imagine what America would be like today if they hadn't.
Democracy puts a system in place which values only the majority vote. Minorities are left behind, stepped on, and even silenced. If democracy is such a "fair" system, then this wouldn't be allowed to continue.