Hmm yeah it's quite badly written. Either way, let's just say it's an example of a place where one can look stuff like this up.
"Ending whiteness" does not mean "killing all white people" or "eradicating all European cultures" or whatever the parent comment was implying. (Or am I reading too much into it?) Though perhaps you can find some moron calling for that on Twitter.
Are other phrases of the form "ending ____ness", where ____ is a racial qualifier, also acceptable, then? Someone using that term could similarly argue that they're not advocating for the eradication of ____ people - just the identity and behavior associated with ____ people.
Are you arguing that calling it "whiteness" is a bad branding move by the sociologists? In that case, I fully agree. There's other similar bad branding moves like "toxic masculinity" or "racism = power + prejudice". I wish they would change those words.
Or do you mean that sociologists who speak about "abolishing whiteness" secretly mean "abolishing the behavior and identity of white people"? No I wouldn't agree with that. I think they mean what they say, and when they tell you their definition of "whiteness", that's what they're referring to. Not some other thing.
Maybe you could look it up instead of dismissing it out of hand
https://en.wikipedia.org/wiki/Whiteness_theory
Feel free to disagree afterwards, but the words do have meaning. And not knowing them is not an argument against it.