Because we live in a post-political-correctness world, where you are shouted down as racist, sexist, nazi or whatever if you have a not-approved-by-the-mainstream-police uncomfortable opinion. Some of those opinions actually are some or all of those things, but once people realised that it's an easy way to shut someone up, the labels expanded dramatically. You are now labeled a rape-culture sexist if you point out that "equal rights" also means men have rights. You are labeled a slave-holder racist if you point out that there are cases where discrimination goes against white people. And god forbid you say anything positive about a heterosexual white male.
Sadly, people didn't understand that the reason sexism and racism and political extremism are making a comeback tour is exactly that their proponents are being shouted down, giving them this "rebel" feeling that tends to make people stick more strongly to their opinion instead of changing theirs mind.
We should engage racists and reveal - to their and our eyes - what's behind their thoughts. Most often, it turns out it's a simple mix of stereotypes and fear, and once revealed it can be healed. We don't do it because we are also afraid - that if you seriously engage the topic, you have to face some uncomfortable facts for yourself. For example that certain demographic groups actually are more prone to violence, or more likely to commit certain crimes, or other such things. Dissecting that into the parts that are inherent to whatever the trait is and those that are self-fullfilling prophecies (if everyone thinks group A is full of criminals, they are less likely to be given good jobs, leaving many of them no other option than to become criminals). So in a way, the whole shouting match is because the non-racists are afraid to face an uncomfortable fact or two that might shake their simplified world-view.
For the record: I'm a racist. My Bengal cat is different from other cat races and I won't let anyone tell me that she's the same as any street cat.
For humans, even the term is silly as there is only one human race. We extinguished the other ones (Neanderthals and such) tens of thousands of years ago.