Learning the language?

So, last time in the classroom the subject 'integration' was discussed. More specific; everytime when the word 'integration' is mentioned, we think about cultural matters.

One of the topics in this was language. Should someone who decides to live in another country learn the language of that country?
I personally think immigrants should be able to choose for themselves if they want to learn it, but they have to take responsibilities for their choice. I'll try to clarify:
I know a guy who owns a car repair shop near Antwerp. Not for regular cars, but pre-war luxurary sports cars; Lagonda, Bugatti, Bentley, etc... The guy is British and has his shop already for several years, but doesn't speak a word of Dutch. When I met him, I asked him why he doesn't learn it. "Quite simple", he said, "99% of my customers are from other countries. My shop is one of the best known all over Europe in this market and most people who come to me don't know Dutch either. I see no reason why I should learn it. I have everything I need and I earn money in this shop this way."
That's what he said to me, and I think he is 100% in his right to say so. He's able to care for himself and doesn't need any help from Dutch-speaking persons to live here.
On the other hand, I know another guy who immigrated to Belgium several years ago, doesn't have a job, and also doesn't speak a word of Dutch.
He sollicitated a few times, but every time again he didn't got the job because he didn't speak Dutch. After a while, he grew tired of this and just stopped applying for a job. He just has his unemployment benefits, doesn't care about working nor learning the language and everytime when he needs Dutch he demands tolks or translations...
This is unacceptable I think. In cases like this, the government should take steps, like perhaps scrapping the unemployment benefits or more actively persuading those persons to either find a job or learn the language.

So, in summary, do I think someone moving to Flanders should learn the language?
I don't think the government should make it mandatory, as long as they can live and take care for themselves independantly. The moment this lack of knowledge of the language is causing problems, steps should be taken. That said, I personally think an immigrant should take the initiative himself to learn it because, as I mentioned in my previous post: "Why is it so important to learn the language of a chosen country? The better we can communicate with each other, the better we can understand each other. If we understand each other better, it's easier to harmonize and co-operate."

Culture consists of many more things than just language though. I just think the only critaria should be that culture shouldn't conflict with law. As long as that's not the case, everyone should be able to keep and show some of his/her culture. During travelling, I often went into bigger cities that had a Chinatown, Little Italy, etc... and I thought it was interesting to see those places.