These statistics almost always willfully ignore the fact that many of these people have negative net worth; it's entirely possible that I personally have more wealth than 10 percent of the world simply due to their having negative wealth.
Should somebody who thinks inequality is bad ignore statistics that don't ignore people with negative net worth? If so, why?
Oh, and from the report:
"The average wealth of each adult belonging to the richest 1 percent is $1.7m, more than 300 times greater than the wealth of the average person in the poorest 90 percent, although for many people in the bottom 10 percent their wealth is zero or negative."
So they didn't ignore it anyway.