Catch can confusion...

[DK91105]

So I decided to add a catch can to my 2019  5.3  after seeing how much carbon build up was present on the valves during a recent repair. I looked around a bit and settled on the k&n unit after seeing they were pretty much all the same for the most part.  When I got it I looked at how it connected and was surprised to see that the hose on the passenger side valve cover is not altered at all during the install.  When I removed this hose for my repair it was clear a good amount of oil is passing through it. How can these catch cans be effective with only the drivers side hose being addressed?