Why collinearity matters, or doesn’t matter

This makes sense to me

But then there’s this reply, from someone who knows a lot more than I do.

Conclusion: don’t trust everything you were taught in a statistics class. Like any other real academic field, there’s a whole lot of nuance that’s lost when you simplify things enough to teach undergraduates or grad students who are only interested in applying statistical tools, in the hope that they give you the ‘right’ answer.