"Mediadefender doesn't count because the users install it"...sound familiar? if you go by THAT metric guess what? Windows is bug free! Yay, there are no malware infected systems, hey security guys, your all out of a job LOL!
Hate to break the news to ya friend but guess how the vast majority of malware spreads? PEBKAC and this proves that Linux is JUST AS VULNERABLE as any other OS. And can you show me ONE zero day that was caught and fixed by a user and NOT a corporation? Just one? You can't because you are falling for the many eyes fallacy that states because something COULD happen it HAS happened. You and others think because the code COULD be audited it HAS been audited with ZERO proof to back it up. Well by that logic since there COULD be zombies there ARE zombies...but I don't think i need to start carrying a shotgun to kill the undead, do you?
Since you seem like a normal person and not a FOSSie, which are like a Moonie only with FOSS as their religion you might want to read this which quickly and concisely explains why its a lie better than I ever could. Oh and just FYI you want to see a FOSSie go absolutely apeshit? Give him a TMRepo link. Of course just as a flat earther hates science so too does a FOSSie hate TMRepo because it has reduced their tired old talking points into cliches. I could take every pro Linux rant here and reduce it to 5 TMs or less, know why? Because its the SAME TIRED SHIT, for 20 fricking years they have been using the same tired ass excuses, "works for me(TM)" "Linux has more drivers(TM)" "Stable ABI nonsense(TM)" its the same shit.
But many eyes is just a variant of the man month. It doesn't work, isn't ever gonna work, and frankly just because you have the source for a low level subsystem doesn't magically give you the knowledge and experience required to repair that system. it would be like saying if I gave you the blueprints you could fab some O-Rings for the shuttle, not happening.