Move along, nothing to see here.
It's about KEXTs. They're a boon of Mac security since I can remember. There was a time when Apple refused to service Macs if certain KEXTs were present.
The point is: I, and Apple, and others, firmly believe the average user does not need to install KEXTs, ever. If you don't understand why, I'll give you a hint: It's in the first letter.
Now, there's a small subset of (non-average) users, who need to install software that cannot, technically, be run without KEXTs. For these users, the way to install KEXTs easily is kept open. At the same time, those small subset of users are experienced enough to jump through the hoops to uninstall (it is not that hard as the article implies). A point could be made that making installing KEXTs should have a bigger hurdle than it does now, with KEXTs being lumped into the same category as unsigned, but safe for most users, software.
The bigger problem here is the exampled application, BlueStacks, installing a KEXT. Because its purpose -- running Android apps -- does NOT require KEXTs. A quick google gives me at least two more software packages that can do that, without KEXTs. So it's either a lazy developer (using KEXTs is easier to program than not), or it's on the track to being malware.