When it first came out, the page illustrating mountain waves was quite horrible, and we criticized it:
Fortunately, that didn't last long. A few months after its original publication, the course was updated and greatly improved, although it still wasn't perfect:
Yes, there is still a fair amount to criticize here, but this is probably the limit of what a typical airplane driver needs to understand about mountain waves. After all, the target audience of the Air Safety Institute seems to be airplane pilots, exclusively.
Which is a shame, since the pilots of gliders, helicopters, ultralights, and balloons probably could also use some well-made refresher courses on safety.
P.S. You should join AOPA.