Cardkid was breaking WotC rules by selling outside the US, and they were punished for it. Someone on MOTL who lives in Canada was allowed to order from them, which is against whatever WotC makes their distributors sign. The Germany thing may or may not be true, but either way, they broke the rules, the end.
My understanding is that the "region" that these sellers can sell to is the US & Canada, so by selling to Canada they did NOT violate policy. However, they are also not supposed to sell to anyone if they know that that customer will in turn be reselling outside the region. So, it is the fault of their CUSTOMER, not THEM, in my opinion. I hope the jerk is happy with how many people they've screwed over this way.
I will say, however, that this was all quickly learned as I tried to research the WotC policy after receiving my own copy of the email - so I admit some of my understanding may be flawed.
I just want to say, however, that I have ordered from TheCardKid for every set since Lorwyn. They have INCREDIBLE customer service, and (with only one exception - M10), I have always gotten my order on the day of release (their distributor had a delay on M10, so my cases arrived the following Monday instead).
That all said, I think that all of the sellers like TheCardKid need to do a MUCH better job letting us customers know what WotC policy is. I don't think I ever read ANYTHING about limitations on what I could do with the product after it was in my hands!