As Ekona says, it's because they are arseholes, not because they're driving 4x4s. I occasionally drive my father's RR Vogue if I need to transport something that won't fit in the Zed... I know it's dimensions, and I know how much room I need to use.
What I don't like is how people (if you can call them that) who try to bully you off the road because they have an inferiority complex. In my view, there are 4 types of 4x4 driver (arsehole category):
1. Bully you off the road - inferiority complex
2. "Soccer moms" taking their kids to school, blissfully unaware of their surroundings
3. Executive businessmen who don't give a toss about who you are or what you're driving - he believes he is superior to you in every way and needs to show this.
4. The "size matters" idiot who thinks that because his/her car is bigger than yours, they have priority and you should bow down to them.
On moments like these, I have no greater wish than to equip myself with a tank, and drive at them. See what they do then.