a) Windows is a piece of crap when it comes to staying clean. If it wasn't, Microsoft wouldn't have to go after people like this. Not joking but I clean out a fair number of PCs every year and they are crawling with malware.
b) Users are dumb and install any old crap on kit if prompted to. Microsoft's SmartScreen did very little to prevent this.
In the fallout from this, people are getting hurt. End users are getting their PCs and data stuffed and companies like this lose their reputation and business because they are a convenient mule (as are the end users) for malware pushers who's job has been made easy.
And don't give me the crap about probability based on the sheer number of windows machines or the plain bullshit security statistics. They're a pretty easy target as the architecture of Windows is incredibly complicated and they're playing plug the holes rather than designing it properly to start with. For ref, I know the NT kernel, win32 and CLR inside out and no longer would I poke it with a stick.
So, there's nothing here that's unique to no-ip.com's case. The problem is that Microsoft spewed out crap for years and people are suffering because the only way they can contain it is to scorch the earth.