No, the issue here is clearly about white people using blackface in any circumstance, which has been almost universally understood to be a racist act, given what our history has been, e.g., white performers using blackface to demean and promulgate stereotypes of African Americans. That history is very pertinent to this issue. 

I read what this law professor said, but I'm not buying it. She said she wore blackface to the Halloween party to "teach" about Dr. Tweedy. At a Halloween party? I consider this holiday to be, probably, the most inclusive of all our holidays, the one least likely to exclude any particular group for any reason. So that's the occasion the professor chose to do this? Why not "teach" the history of Dr. Tweedy during her class lecture? 

The other way to look at this issue is, have you ever seen an African American person ever use "white face" to make a point about white people? I've never seen it. Why is that, do you think? Maybe because it would be seen as racist?