Microsoft should indeed know, but as many computer experts will tell you, Microsoft is notorious for security lapses, and often relies on customer feedback to identify 'holes' and then makes patches. However, as it is by far the biggest player in the patch, we have to live with its foibles.
It is also the case that most ISP providers nowadays give you a package with a security system included, either Norton or macafee or similar. While this is not compulsory it can sometimes lead to 'conflicts' within your Machine if you try to avoid using it. BT is bad for this and will always keep trying to direct you back to their 'system'. Of course having more than one system operating will be even worse as they conflict with each other and you get no benefits.
Each player is trying to 'lock' you in as much as possible to stop you swopping to another ISP. Internet fraud is also the biggest crime area on the planet, and can only get worse as more of us are 'encouraged' to do everything on line. One can also have a 'Frankenstein' moment and believe that at some date in the future we will all be 'controlled' through the Web and some 'master' will be in charge. Heaven help us.