As the program chair of a small conference for a number of years I sent out for three reviews about 50 papers per conference. I would say that such bad reviews (Reviewer 2) were rare and resulted in my leaving such reviewers off the next conference reviewer list and NOT passing such reviews to the author. FYI, having received such bad reviews myself, I understand they exist and are harmful.
What I found more difficult is the number of reviews that just checked the boxes (accept/reject, relevant or not, requires editing, etc.) and provided little or no comment. More than 80% of the reviews we received were like this.