Headline is wildly misleading. The research actually says that they are less likely to use "words related to competence (that is, words about ability or status, such as 'assertive' or 'competitive')." Something like "White liberals use less assertive/forceful language when interacting with African-Americans" would be more appropriate.
I agree that this could be seen as patronizing and problematic, however well-intentioned. But the headline is just awful.