I think parent's point is that, to an extremely accurate approximation, none of the elements on Earth come from the Sun. Hence, while it's true that trace elements didn't come from the Sun, it's weird to focus on that because nothing else did either.

EDIT: And it's also weird to tie this to the fact that the Sun won't produce elements heavier than iron through normal (i.e. non-nova) fusion late in its life since that has nothing to do with it.

Panspermia isn't widely accepted, but stellar nucleosynthesis/supernovae are generally accepted to be the source of the heavy elements.