It's not how I plan, but it makes perfect sense. If you're not going to park hop, then avoid EMH parks. If you're not going to be there for those EMH times, then avoid those parks.
For me, I'm a "rope drop" person, and will park hop with no problems. So I love going super early for morning EMH and doing the most popular attractions 10+ times in a couple of hours before the crowds start showing up, or staying late and doing almost the same. The rest of the time is spent at another park, or in my room taking a nap, or at the pool, or whatever.
But the reason the planning sites say to avoid those parks is because so many people do one park per day, and thus plan around those hours to "get the most for their money". So if you won't get up early enough, or stay late enough, or limit yourself to one park per day, then staying away from EMH parks is a good plan.