A deer can really damage a car.
You talking about hundreds of pounds of sheer weight.
The term “deer frozen in the headlights” has real life impact.
That isn't the real problem with deer. If they would stay put, there would be much less of a problem. But what they do is emerge from the woods/brush at top speed and the driver doesn't have enough time to react. Even when they are standing still, they will sometimes panic and do unpredictable things.
The bottom line is that the deer population in many areas is way out of control, and there is little incentive to do anything about it. When they try, they have to deal with animal rights activists picketing and filing lawsuits.