Mahmoud, you're beginning to see the problem of bias, but there's a good deal more to it. People like to believe they are secure, and hence, the supposedly "technical" users like to believe they somehow vet their software.

The truth of the matter is vastly different.

Can you name anyone who as actually done a security audit on every single binary and source file they use?

In other words, the assurances people seek by paying for software are fictitious from the start. The very same is true for open source software.