Why did the UW frat Delta Upsilon get a 2-year suspension after 2 guys yelled at 2 trespassers?

Was it because the trespassers were black?

Delta Upsilon fraternity members said they'd had a problem with trespassers prior to an encounter...

According to an evidence packet released Friday morning, two members said they'd found heroin syringes on the property, 644 N. Frances St., and a Bose speaker had been stolen that night....

According to a letter from one of the women, she and a friend decided to take a walk to the lake in the early morning of March 16 and unintentionally walked on the fraternity's property. The members told the women to get off their property.

At least one of the members asked them, "how did it feel to be peasants?" and "How did it feel to be poor," the letter said. The members also told the women that they were among the one percent of the rich and the women should leave....

A bottle was heard to break, but the committee that imposed the suspension did not determine that the bottle was thrown (or aimed at the women). Note that there were no racial epithets: It was social-class taunting.

Originally the university said the fraternity members used racial slurs in addressing the women, but the committee said it could not corroborate that allegation.

Why did the university make it racial? (And why did the women even report this incident? If I were walking on someone's private property and they told me to get off, I'd quickly say "I'm sorry" and leave, and feel embarrassed.)