bitingduck

That's not unusual at all-- I've seen a few steel forks and frames seriously bent back while barely knocking the front wheel out of true. I've done it myself. The most impressive I've seen was someone's Merckx track frame had the down tube bent with a big arc in it, exactly the radius of a wheel and bending the tube in an inch or more, while the ends of the tube were pretty much still straight. It was like something out of a cartoon.

The wheel is designed to take really big radial loads over and over around any point on its circumference. Think about what happens every time you hit a pothole- occasionally you'll trash a wheel, but usually you're just mad at the person in front of you for taking you over it. The fork and head tube are designed to take those loads pretty much pointed up from the road, not back from the front with a large lever arm (the fork length). Forks are generally pretty weak against the kind of force you get when you plow into something like a guardrail at 30 mph and will bend, as would the head-tube to down-tube joint on steel bikes.