It's a response to a previous article, which really did make the argument "unit testing does not guarantee quality, therefore you need static typing". So not a strawman.

The previous article really didn't make the argument "all you need is static typing". It was specifically refuting the idea that "all you need is unit testing" - or at least that unit testing is a complete replacement for static types.

The paper makes a point of reporting that most unit tests could not be replaced by static types.

What of that looks like a claim that you only need types?

The previous article said "unit testing isn't enough, you need static types /as well/". This article is extending that argument to "unit testing and static types aren't enough, you need xyz /as well/".

I believe the point is that there will always be something your current test strategy doesn't cover. At what point do you draw the line?

If unit tests and static types don't cover everything, what says that's enough? And can the justification for that, whatever it is, be applied to "unit tests are enough" also?