You mean those props who visit porn sites, or deliberately download stolen games files or films or apps, and then turn that little feature that blocks content from unknown sources to Off. Or the ones that hack their devices and install custom ROMS etc.
Oh THOSE sorts of people.....
Or just people who don't know what they're installing onto their phone, much like a lot of Windows (and some Mac) users do to install malware. The fact that it's actually impossible on an iPhone unless you jailbreak does in fact make it the most secure mobile operating system, while being able to install what you want with little security to stop you making a mistake on Android does in fact make it the least secure mobile operating system.