"I" am not responsible for someone elses actions. Neither is the pro-life movement. If someone get's violent at a peaceful demonstration, then they and they alone are responsible for their actions and should be treated and charged accordingly.
In principle I'd agree, but things are a little more complicated here. We had a similar "educational display" marching around a nearby hospital for a couple of weeks last summer. These people were far from "peaceful demonstrators" and bystanders were openly intimidated. In reading the history of exchnages between this group and the UofA administration over the years it's pretty easy to see they are taking an in-your-face stance and thus must take some responsibility for the atmosphere they are creating.