Programmers aren't professionals in the sense that he's using. There is no accreditation procedure, there is no regulating body, there is no licensing, there is no code of ethics that must be followed by all programmers, and there is no liability attached to malpractice.
> Note that there are accreditation procedures, regulating bodies, and licensing for teachers.
> So how are teachers not professionals?
Those are schemes for limiting the number of people who are allowed to teach in certain circumstances. They don't have much to do with quality teaching.
If you disagree, the following questions are relevant.
(1) How often does a regulating body discipline a teacher?
(2) In what circumstances are licenses actually revoked?
Feel free to compare the numbers to the corresponding ones for stock brokers. (I don't think that stock brokers are clean enough, so if teachers are worse....)