I would still say it depends on what is actually done during the jump schools. If I had a horse at this level, a typical plan would be to work in the arena on a specific jumping skill after a session of flat work - an example would be to set up a small inviting vertical and practice jumping the left side, the right side and dead center from both directions and leads, then cross paneling from both directions and both leads. If I was satisfied with that in the minimum number of jumping efforts (~8), I would set up a bending line, and applying the skills from the previous exercise, ride it through the middle at a certain number of strides, then outside panel to outside panel adding a stride, inside panel to inside panel subtracting a stride, then cross paneling to ride it as a direct line - another 8 jumping efforts if we get it right the first time. That jumping school is efficient, teaches or refreshes a needed skill, and doesn't create as much stress as drilling an exercise or jumping multiple courses.
If I did that exercise one day, a couple of days later, and the end of a hack or endurance day, I might do similiar exercises over xc fences, or I might ask different questions - jumping from light to dark or dark to light, jumping narrows or skinnys (great follow up the ring school) or related fences. I could probably get this done with no more than 10 - 12 jumping efforts.
In other words, I've accomplished more with fewer jumping efforts.
I guess the short version of my long winded answer is that if you're thoughtful and have a training plan, you can certainly do two jump schools a week with minimal risk to the horse.
What you can't do is warm up and jump around a stadium course 4 - 5 times one day and then do a full xc school later in the same week.
As always, JMO and JME.
I think a lot of the people reacting negatively have seen WAY too many novices overjumping their horses into boredom or unsoundness by drilling the same things, badly, over and over and over again, and with no training goal in sight, because it's fun for the rider. That does not seem to be the case here.
And it's worth repeating that you should put your random FB critic on your ignore list.