If you're going to use the most popular operating system available, then you have to expect the kind of negative attention it gets from hackers, virus writers and dodgy software writers.
If AmigaOS was as popular as Windows, do you think everything would be perfect, no problems like that at all?
Yes, there are aspects about MS's software design that leave a lot to be desired, and that doesn't help things.
But generally, you're responsible for the software you install on your system, if you're not paying attention you'll get screwed. Simple as that.