1. No. But laws are rarely written in a way that people without a lawyer can understand.
Do you fully understand every EULA you agree to? Do you keep up with changes to the licenses of everything you use on a daily basis and immediately update your processes based on any changes you don't like? Do you have the expectation that everyone can do such a thing? Is there the expectation that everyone have a lawyer ready to review everything they touch?
2. They probably didn't. But Bricklink has such a footing, they likely thought it would be worth whatever hassles came up.
Lots of people didn't like the idea of Bricklink being bought by LEGO. Partly because it increases LEGO's control over the building block industry. Partly because it seemed to have come out of nowhere.