And remember coders to review all closed-source software. You have even less of an idea who worked on it and how much time and effort they put into it to make it secure.

But wait, you can't review closed-source code. So I guess you are completely at the mercy of someone else. But a company is liable for security holes in their code, right? Well, no. Read the EULA and you will realize that YOU are responsible for their bad code. Utilizing closed source is a COMPLETE act of faith in other humans.

I think I'd rather trust thousands of eyes, some possibly malicious, than trust dozens of eyes, some possibly malicious.