Speaking as a personal trainer... he's right.
You can go get your certificates and not know how to coach a pushup. I mean that literally - there is not list of exercises you must be able to coach before being certified as a PT. What's really needed is some sort of apprenticeship system.
If I owned a gym, I'd take on unqualified trainers. I'd tell them: "You're an apprentice. Sign up for this TAFE course, it's two nights a week for a year. 30 hours a week you'll work in the gym. In the beginning you'll just watch, and you'd better be taking notes and asking questions. Over time we'll let you do things and coach people while supervised, and gradually drop off the supervision. As well, you must pick a goal which should take around 6 months to achieve, whether it be to squat 100kg for 20 reps, run 5km in under 20'00" or whatever, you must achieve this goal to pass the course and have any possibility of employment after your apprenticeship, achieving this goal will be 1hr of your work each day."
The point of the supervised coaching I think should be obvious. The point of the goal is that they should have experience of training towards a specific goal, a goal which is difficult enough that progress towards it won't be linear, there'll be steps back, maybe a minor injury or illness or two. This will give them insights on training, and prevent their under- or over-estimation of what people can do.
One of the trainers sent us out some example Crossfit workouts suggesting we try them. One of them was "Linda", deadlift 1.5x bodyweight, squat 1x BW and clean 0.75x BW, first for 10 reps, then 9, then 8, down to 1. This trainer is a bosu ball trainer, he has never even done or coached anyone to doing a single with 1.5xBW, and he's suggesting we get them to do 55 reps? Had he himself ever done this, he'd know it was a stupid workout and not sent it to us.
This is the context in which Woodske is ranting.
Note that if I sent this out to my workmates, none of them would think it applies to them. "Oh me, I'm a great trainer, it's just those other guys." For my part, I know I've a lot to learn, that's why I'm going to the Starting Strength seminar in February. I'm the best in my gym at coaching the slow barbell lifts, our manager is best at the quick lifts. Elsewhere there are many better trainers and coaches though, I've still much to learn.
Most won't do that sort of thing. Again, this is the context in which he's ranting.