They say the plastic blocks WERE patented, but Lego (allegedly) didn't care or perhaps as you mentioned the patent didn't apply in Denmark according to some commenters as well.
As the article notes, Lego has been very aggressive pursuing perceived design violations.
http://www.cracked.com/article_20025_5-world-famous-products...
http://birthmoviesdeath.com/2014/02/06/kiddicraft-the-compan...
They say the plastic blocks WERE patented, but Lego (allegedly) didn't care or perhaps as you mentioned the patent didn't apply in Denmark according to some commenters as well.
As the article notes, Lego has been very aggressive pursuing perceived design violations.