Linux, Unix and other Unix-like computer operating systems are generally regarded as very well-protected from/against computer viruses,but they are not immune to them. I am inside my house, I am protected from the weather. My house has been painted, it is protected against the weather. Maybe a firewall gives protection against viruses whereas the operating systems are protected from them? Thinking out loud!

Ah sorry misunderstood you... But it was only about the right preposition for 'protected' and 'immune'. Yes, the sentence does get long this way, I wont change the wiki page.

My version? No, I have not written the text. :) I just read it and thought, this is clumsy English. I would have written it like you just did.

I think your version works pretty well, but using your propostions the sentence would need to be rewritten: Linux, Unix and other Unix-like computer operating systems are generally regarded as very well-protected against, but not immune to, computer viruses. The trouble is that this sentence now looks slightly clumsy compared to the original which may (or may not!) be less accurate.

I agree with you. The moral of the story is that this may have been written by a native speaker, but that doesn't mean that it is perfect. We all make mistakes, or say things in a way that might not always be clear to other people.