Why defend a man who does not pay royalties to inventors?
Without knowing the details of their arrangement it isn't proper to have an opinion either way, but I thought it relevant to point out no initial royalties *may* be entirely within the original agreement (as it was with me and some others who have worked with Meffert). It is not at all uncommon to have contracts where there is a fixed up front payment and royalties only follow after a certain number of units sell to recuperate the production investment. This is how contracts used to work in Video Games in the 1990s, at least.
This forum has many accounts of people being unhappy with less than prompt customer service but in most cases the issues are resolved with a bit of time. I would hope this might be the case here. It is entirely possible Meffert has decided to burn his reputation with puzzle designers and simply ignore his obligations, but that wouldn't be my first guess.
What his actions differ from the KO companies?
I can think of two differences right off: He entered into an agreement and gave some initial compensation. Without this initial production I am fairly sure the recently copied version would never have existed. The investment to go from Shapeways design to injection design is not nearly as easy as copying an existing injection design.
This does not excuse anyone ignoring their business or ethical obligations but is a significant difference from how blatant copiers work, who never bother to get permission nor offer anything to the original designer.
I don't know if you are aware Dave, but the Flowerminx has also been made by another manufacturer and retails for roughly $7.50 - $8.
I believe someone had mentioned that. I can't say I am too surprised other than being perhaps a bit flattered someone thought it worth copying. I would not condone anyone buying KO versions.