...huh? This is very much not true. The most difficult[0] encounters happen on the Genocide route, in which you powerlevel like it's a normal JRPG until the encounters run out. Pacifist is only slightly harder than a "No Mercy" neutral run[1].
For the first two thirds of this article I was screaming "BUT WHAT ABOUT UNDERTALE". Toby Fox basically wrote the book on the moral quandries of killing monsters in video games, and this article does not do his work justice. It feels like the author wanted to briefly mention it at the end as a way to cap off the essay. And, while I haven't played Shadow of the Colossus, I suspect the inspection of that is about as surface-level as the tacked-on mention of UNDERTALE at the end.
I feel like I just read a high school English essay.
[0] Mechanically and emotionally.
[1] As in, a run in which you kill everything you see, but do not exhaust the kill limit.