Security is a pain
Lets be honest, keeping a machine secure at work or at home is generally inconvenient as the requirements will make simple tasks less so (or occasionally impossible). As a result many people will cut corners as they really don't understand the risks.
I've never used my own equipment in the workplace - if my employer wants me to use a computer he can pay for it - and I am sufficiently paranoid never to have picked up a nasty at home. But this is made easier as I don't frequent social media or pornographic websites (is there a difference?) so I am less at risk than some. Also, I very rarely use public wi-fi hotspots and when I do it is from very tightly locked down linux device.
Amusingly, the only time I ever had a problem was at work inside a pretty solid corporate firewall. I had been issued a new laptop and I had to plug it into the office network to pick up the mandated firewall & a/v packages (no pre-installed corporate setup at the time). During that process the thing picked up no less than 6 viruses. IT support tracked them down to a guy who had taken his laptop home and let his kids install games on it ...