My professor is not teaching his online course himself, but uses publicly available videos instead. Is this appropriate?

It might not be the best way to teach, but if the professor has tenure, that person can probably get away with it. Face it, there are some lazy professors. Of course, that prof might simply think the class is not important enough. If you believe that you are not getting what you paid for,don’t take that professor again. If you take a another class with another professor, and the same thing happens, you might want to drop the class, if at all possible.

I say this because students have different learning styles. Some learn better through lectures, some through more hands-on instruction, some are aural learners, and some visual. If you are not getting much out of the class because of this, change classes.