Two real-world examples of strained usage come to mind. Opponents of the modern filibuster have taken to calling it “racist” because it has been used for racist ends. This implies a kind of contamination, a rather unsophisticated perspective given that this “racist” practice has been readily supported by noted non-racists such as Barack Obama (before he changed his mind on the matter). Similar is the idea that standardized tests are “racist” because Black kids often don’t do as well on them as white kids. If the tests’ content is biased toward knowledge that white kids are more likely to have, that complaint may be justified. Otherwise, factors beyond the tests themselves, such as literacy in the home, whether children are tested throughout childhood, how plugged in their parents are to test-prep opportunities, and subtle attitudes toward school and the printed page, likely explain why some groups might be less prepared to excel at them.
Dictionaries are correct to incorporate the societal usage of racism, because it is now common coin. The lexicographer describes rather than prescribes. However, its enshrinement in dictionaries leaves its unwieldiness intact, just as a pretty map can include a road full of potholes that suddenly becomes one-way at a dangerous curve. Nearly every designation of someone or something as “racist” in modern America raises legitimate questions, and leaves so many legions of people confused or irritated that no one can responsibly dismiss all of this confusion and irritation as mere, well, racism.