> as long as your mechanic fixes both, why would you care that they wereboth just single line-items in your bill?
You missed the key words: "assign the same importance".
I (and most other people) care more that the brakes work, because they are more important. And I also care more that security related bugs get fixed, because, just like with fixing brakes, failure to do so has a potential to cause more damage.
Of course, Linus and people supporting his view (that contradicts common sense) will come up with complicated philosophical reasons as to why they are right. All of that cannot change the above simple fact.