Windows is one big piece of spyware.
Spyware schmyware! Are you not aware that you can set up Windows with local account, and provide no personal information? Okay, so Windows is not open-source, but if you're personal information is also "closed-source," spyware problem solved. If you're privacy is a significant concern you're probably already using Tor or VPN for IP masking. Unencrypted data you transfer through the internet is more likely to divulge personal details than anything I'm likely to save on OneDrive, and a warrant isn't required.
Together with all the known and unknown vulnerabilities at any given time, the risk of getting compromised with a windows system is higher than getting compromised using a mac or unix system.
Of course there's more risk to Windows than other systems, because hackers want results. If everyone took your advice and started using Linux, do you think that hackers would continue to only target Windows? Hacking a Windows box, or writing malware to attack Windows isn't any easier than it would be for other systems. In fact, with all the closed-source anti-malware features built into Windows these days, I would reckon it's harder. It makes perfect sense that hackers would target the most commonly used operating system just because it's the most commonly used operating system, regardless of difficulty.
It's perfectly fine to not like Windows because Bill Gates, NSA, ABC, XYZ... but, it's disingenuous to promote this theory that if you don't use Windows somehow your privacy is magically protected, and you're invulnerable to being hacked. That's far from the truth. If you don't know how to keep your data private or your computer safe, no OS will protect you. Educating yourself, your family, and your colleagues is the only safe course of action, and promoting any alternate theory is dangerous.