Certainly : acting like a fool in your place of employ is bad. However, using your analogy as an example, what's happening here is also a bit like those 3 AM campus shenanigans that occurred while you were a student being held against you when you go looking for a job - since Riot is screening potential employees based on their game history.
If Riot screens applicants based on their LoL behavior, then why shouldn't Facebook? Google? Why shouldn't any of these respective companies sell said information to other 3rd party companies that want to pre-screen hires?
Ultimately I guess I'm arguing against a fully transparent world, because as happy as I am with my electronic footprint - I'm not sure how happy I am about the idea of everyone in the world who I interact with peering at it with a microscope.