Business lobby: Learn Danish or get out

I don't think the comments of DE and the increase in English in academic teaching is a contradiction. DE exactly wants both. Of course they need a workforce that is trained in English on a level where they can also read and compose hard technical texts, since Denmark has an export oriented economy and companies don't want to spend money on extra English courses for their employees.
On the other hand the economy is doing well and there is little unemployment. Marx already noted 150 years ago that it is not in the interest of the capitalists to have low unemployment since it keeps wages up. For ages, one way to get this problem under control was to get workers from abroad to put pressure on the labor market. Of course the danish economy is in need of skilled workers, so it is a good idea to have people com to study here in order to have them benefit from the good education system. Now the problem is that many companies will still prefer the Danes amongst other reasons for the language. That's why they consider the students leaving a "loss" though this is of course for reasons Sorin points out in his comment, which is th mainstream idea also largely shared in society, academia and politics all over the world.
They should know though, that this won't help much. I don't know how the numbers are in Denmark, but in my home country Germany, it is a big problem that the highly educated second generation immigrant Germans, who are fluent in the German language and culture (as well as their parents') and thus could be the greatest assets to German society, leave the country because they can't stand the daily racism.

The problem is, neither the University, nor the Ministry of Education, not DE can change the mentality here. The general inhospitality towards foreigners is, in my opinion due to specific dynamics in a comparatively small country and can only be resolved through becoming further civilized in the western world and possibly stronger Pan European thinking. It's not only in Denmark, if you have a German license plate in Switzerland for instance, you are in significantly higher risk of getting your tires sliced.
It is true that this has nothing to do with foreigners not being able to speak danish, since some Danes of non danish heritage, how we might call them if politically correct, or non white Danes to be precise have the same problem.
Whatever the reasons behind mandatory danish courses might be (DEs are for sure not altruistic), I think they would make the stay for most foreigners better. Most of the students come with the plan to learn danish, then don't go beyond an intro course for all the obvious reasons, but later regret it, because they are not as involved in student live and end up hanging out with other foreigners.
So if the MoE or KU have a chance to make the stay for exchange students better, it is worth considering.

If so, you definitely won't get the bests. The bests go somewhere to spend their time and energy on their work/education than facing barriers/challenges like language.
One simple question: Why should I come there if I have the chance to go somewhere else? Then you end up getting only the ones had no other choices than being "FORCED" to learn Danish.
I have no problem with making it mandatory for the international skilled workers coming just to work, but that doesn't make sense to me to "force" the international students to do so. It's somehow discrimination, too: International students end up spending time and energy on something that Danes won't! This way, you indirectly help the Danish students to become more competent. That is NOT right!
[I've been in Danish system for more than 6 years. I've been representing PhD students at Life, KU, in the board of PhD studies. I've been also representing PhD students in Denmark at the student board of NOVA-UN, Nordic countries. Based on my experience, I strongly tell you: this proposal is the most dumb thing I've ever heard!]

I totally agree that Denmark should try more to keep international students here once they finish their studies. But why choose such a restrictive (and unheard of) measure like making Danish mandatory? As an economics student, I am a firm believer in the power of incentives. Offer them clear and appropriate incentives and students will take up Danish lessons. Keep in mind I said clear incentives, not just "encouragement".

Let's face it, Danish is hard. Most of the students that take up Danish seriously (not just the fun pre-semester Danish course offered by the university) are those that have a clear plan of staying here afterwards. Those who are undecided about their future see few reasons to start Danish while doing their study here, so when time comes to make a decision, they would probably return home, since it's extremely hard to enter the Danish labour market without knowing the language (as it should be, we can't expect Danes to adopt English just because of us).

In the end, it all comes to this: If the government is serious about attracting foreign talent then it should focus more on foreign students learning at Danish universities. It would be much harder to attract a young graduate of other good universities than to retain someone who lived here, knows what the country has to offer and is acquainted with its people and society. If that person already knows Danish, then mission accomplished.

If this is not a priority, no problem. Then each foreigner should assess better his or her own priorities and decide whether he or she plans to stay in Denmark after graduation. But then, don't complain if many of them choose not to...