Yes - but some people; the people you're talking about - Schools, Shops, etc - don't have the know-how to close these holes. So they'd have to get somebody in who could; some of these people who could will naturally be unpleasant and do bad things. He'd be prefectly within his rights to do whatever he wanted to bug the entire system even! This is not at all the safety that people want, that they get from Windows. There's nothing the general user can do on Linux which they can't on Windows - but there are things on Windows which the general user can't do on Linux. In fact - a great deal of the best Pros wouldn't use Linux. Just like the average test scores are higher in Females than Males, but Males get the best scores. Just as Linux users get the highest average Pro-Scores, but the Windows users get the highest Pro-Scores!
I hope you and I stay on here long enough for me to prove that to you and all of you!
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.