Hmmmm...George Morris, Littauer, Chamberlin and others with a pretty impressive track record disagree with you. The US Cavalry manual said:
"Toes turned in stiffen the ankles, force the heels out, and cause loss of contact of proper parts of the calves of the legs. This fault reduces the security of the rider and makes the correct use of the legs impossible. Excessively turned out toes stiffen the ankles, put the knees out of contact, place the rider on the back of his thighs and disrupt the seat."
Where is that sweet spot? It varies for each person and depends in part on what horse they are on. It could run as little as 10 deg, or as much as 45 deg.
Just don't duck foot it. The comment I was referring to just said - stick your toes out - which to a novice rider and be interpreted as the latter part of your quote. Actually - I'm pretty sure I paraphrased that last part - that excessively pointing your toe of leads to your knee coming off and rolling onto the back of your leg. I agree - you want a natural "roll" to you leg so your toes come off the horse naturally. Really the depend on how "far" is where the inseam of your calf falls on the horse and how your ankles "attach" from there.
But you don't want to STICK your toes out to gain false balance and create a whole other tub of troubles.