To be fair, the article does make a distinction, saying the other parts weren't part of the holocaust, necessitating a different name for everything else.
It doesn't deny that other stuff happens, it just defines the holocaust as not including them.
Personally, I never knew the scale of the non-holocaust parts of the holocaust era until reading this today, and I expect it's because of the narrow scope of the term's definition. So I'm sympathetic to konjin's view even though it's just a question of definitions instead of a question of facts.