The Bitcoin blockchain is helping keep a botnet from being taken down

I don't think the story here is "ban blockchain so we can end botnets". The story is "it's going to be harder to take down botnets".

Or rather, the story for the moment is that it's not. The last section is about how it's cheap to disrupt. But that will probably be solved pretty quickly.

In some detailed examinations, if you're quite pedantic, there are no "from" addresses in Bitcoin. Which I only mention to lead into: more concretely there may have been no easy way to tell when there was a spend "from" a certain address with the tools they were using to check. "Have I been paid yet?" is a much better supported use-case in Bitcoin than "Hey let me know when I just sent out money", so it's quite easy for the tooling for that to be easier to find. And malware authors are pretty lazy generally.