College is expensive - often prohibitively so, as well as time consuming, and college education is generally more than is necessary to exist from day to day. Literacy classes, as I understand here in the states, are offered at low or no cost, frequently on a flexible schedule that doesn't impact the work schedule.
That's true, although remember that I'm not talking about its actual cost so much as its perceived cost/benefit analysis and we have to include psychological factors here. What about the cost to your self-identity, pride and community spirit? What about being perceived as a sell-out by your friends?
Also if your language skills force you into a lower paying job, you may be working double-shifts to make enough money making it harder to attend these classes. You may know friends who took one of those classes and still can't find a job. You may feel discouraged by a lot of your own negative experiences with the job market and not want to continue trying.
I could speculate all day, but ultimately I think the people in government in Rotterdam will need to consult with some qualified sociologists who can study the problem locally and see exactly where the breakdown is happening.
If one of the reasons that they aren't getting the job is because they can't speak the language, it only makes sense that learning the language would eliminate that particular hurdle.
Then these people are either very stupid and lazy, or know something we don't because it seems en masse they are refusing an apparently perfect solution to their problem.
Personally, I don't suspect that it's stupidity or laziness (well, not for everyone. Maybe for some of the people that's the problem but that's harder to fix).
Even if that particular employer is discriminating against them, knowing the language would help in so many other dealings on a day-to-day basis.
I don't think that's entirely true and that's perhaps part of the problem. If they are living in small isolated and insular communities with their own jobs, media, radio stations and dating circuits, they may go entire days without speaking formal dutch. Their own pidgin language sounds close enough to dutch that they can probably manage those conversations already with probably just some minor frustrations and misunderstandings.
The self-supporting community is probably very helpful on a day to day basis, but may discourage looking outside the community in the long-run.