I don't think there's anything wrong in promoting a business on Steemit, however like you mentioned, it's the flavour of the post, from the headline to the visual design of it, it screams scam.
To be fair to him though, seeing as I don't actually know the guy or have checked out his courses. Udemy.com is a bonafide, top quality site, so it's possible his courses are valuable, he just has a terrible way of presenting them.
I agree with your comments on Udemy.