League of Legends does not use a Kernel-level anti-cheat. If you had actually read the article in question, this would have been made clear.
Mate you are chastising him for not reading the article and you are contradicted by the first paragraph.
Code running in the kernel context is different than code running in the user context. Another process can modify user context, whereas it is expected that code running in the kernel context is "much harder".
A dedicated attacker could write kernel code which does the modifications, however this raises the bar and the anti cheat software could the game from running if it detects any unsigned drivers.
All this does is raise the bar to where the game is run into virtualization where the host OS can inspect the guests memory and infer details that way. The cat and mouse game goes on forever, the trick is to make it just hard enough so that the average person who wants to cheat will not not have the time, patience or financial incentive to do so.