I think backdoors are left in these apps on purpose. Making a backdoor look like sloppy coding has become an art itself.
MS had to stop bulking up its systems so much because of competition from Apple and Linux. It would be nice if similar competition stopped the backdoors.
The worst backdoor is having USB keys automatically run executables. How can I ever trust a company that does these things?
That's the way the Iranian nuclear bomb program was derailed: a virus was spread on USB Flash drives that only infected specific nuclear engineering software for Windows computers with specific Arabic tags! So, in this instance I'm kind of glad that capability WAS there... It set back their nuclear program by at least two years I understand!
Incidentally, my understanding is that does not happen on Macs. Shhhh. Don't tell any one.