While sending passwords in plain text via e-mail is something that should be frowned upon, the e-mail itself is not evidence that they store your password in plain text.
I think the advice you give is interesting, though i'm more curious to hear why you think people should use a recruiter in the first place? I can see the potential training or retouching of a CV, but i feel somewhat confident that i got that right. So then, what's left?
And isn't the harassment a trade-off for, as what i perceive, being too lazy to find a job yourself?
In the Netherlands the situation is pretty much the same. I personally never use recruiters to find a job. I had put my CV shortly up on a website and got harassed months after with job vacancies that didn't even relate to my CV. Most developers around me also hold a grudge against recruiters and see it, like mentioned in your article, as a necessary evil.