Those flappy fucks caught hands somewhat often when I was a kid, they always tried to steal my bread when Mom took me to feed the ducks (and yes, I know how bad that is, I was like 8-12).

the young, elderly and smaller individuals can get a broken bone from a goose being startled and falling over

That's the real cause here.

If you stand your ground and show that fucker who outweighs the other 3 to 1 or more and doesn't have hollow bones, it won't bowl you over.

knock down a full-grown adult and cause scrapes, stitches, even broken bones

Bolded the important parts.

Falling over for any reason can cause scrapes, stitches, even broken bones, regardless of the instigating factor.

An adult weighing three times as much of a goose doesn't fall over because the goose is strong. They fall over because of being startled into losing their balance, which is a feat a sparrow or a mouse could also accomplish.

Propaganda from big goose. That article was literally funded by goose & co.