Because they've chosen not to pursue citizenship. There's a simplified path that anyone in this situation can utilize. I don't see how giving them the choice and allowing them to live and work in the country indefinitely even if they choose no is in any way "un-democratic".
And if you're suggesting that 30 years is not enough time to learn the absolute basics of a language, that is just utterly ridiculous. Not nearly as ridiculous as comparing this to the slave labor that built Dubai though.