My hate for AV and Spyware products

So, I have etrust, and I have the new microsoft defender anti spyware stuff..

So, some rogue exe downloads itself (I probably helped it, but all the same) the av software didnt say "Hey stupid, you dont want this" the spyware thing didnt say "Hey stupid, this is bad news"

So, I decided to do a full scan, and some hidden baddy file on my system woke up and trashed it. Its an odd thing, it doesnt seem to be running unless you somehow open something to trigger it. It does have a name, but its one where it will suddenly tell you your login has expired it cant do this that or the other and your machine basically just stops..

Whats the point of half this software thats supposedly monitoring my system if it just lets it do it anyway?