but there is a huge difference between:

1) racing, and normal motorcycle use -- like the kind of accidents you run into commonly differ hugely

2) you being able to afford a end of the line product or being very budged constrained

and this are two important aspects completely ignored in this discussion

It's partly true. I used to ride dirt bikes with full protection everywhere and it just makes you hot, I went to thinner protection and with more focus on getting the basics right: protect your feet at all costs, and protect your head. Aside from that, you're mostly fine. I still wear some light armor on knees and upper body though.

Offroad is completely different to circuit racing in terms of the kinds of protection required.

For interest, and to the point, Toby Price gearing up for the motorcycle leg of the Finke after completing the 4 wheel leg:

https://youtu.be/WKRcUtVGP4M?t=274

Why are the feet so important?

Well, perhaps not more important than other body parts, but more likely to be injured.

Every basic motorcycle safety class will urge you to get good boots. I just wished I had heeded that advise in time instead of buying them after my first crash ;-/

Because if you fall on dirt, there is a big risk you will mess up your feet or ankles without proper boots that protect them.

Well, I rode on the road but can imagine the same goes for off-road, but the right pair of boots makes a huge difference in one’s confidence and ability to securely put one’s foot down at a stop, especially if it’s a bit slick from oil, or loose debris. That, and you can imagine an object hitting your foot while flying down the highway at 80mph feels very different when you’re wearing riding boots vs. wearing vans. Then there’s the whole, sliding on assault aspect.

What racing community? Circuit racing? If so I really think you're wrong. But always happy to learn something new.