Why would that be a reason? Why would they want to harm their existing business by acting like that? How would they benefit anyway? Installs aren't worth shit.

Why would that be a reason? Why would they want to harm their existing business by acting like that? How would they benefit anyway? Installs aren't worth shit. They'd be better off going to a forum and buying thousands of installs for their malware if they wanted to spy on people, the kinds of people renting out their facebook accounts certainly won't be particularly interesting targets. If someone wanted to "install a backdoor or steal your personal files including but not limited to personal photos, electronic tax records, banking information, etc," this would be the worst imaginable way of achieving that.