If someone defaced a statue of Martin Luther King Jr., I guess someone could call it a hate crime. But King clearly represented and spoke for his people. He was their leader and symbol.
Columbus was a work-for-hire contractor for the Spanish monarchy. He had little or nothing to do with Italy except being born there. No way was he a symbol of Italy then, and arguably not now.
If anything, people who hate Columbus are protesting Spain, the West, or Caucasians. You could call the vandalism a hate crime against these groups, though we usually don't prosecute hate crimes against countries or continents. But a hate crime against Italians? No.
For more on the subject, see Columbus Day 2010 Protests and "Sad, Hollow" Columbus Defenders. For more on monuments that shouldn't exist, see Best Indian Monuments to Topple.