I'm sure it's plenty strong.... Stronger than the quill stems you and I have been pounding for years.... Although I doubt that bike actually sees much use.
I bet those lugs still need a ton of final shaping and finishing. 3D printing, while precise, doesn't produce the greatest surfaces cosmetically. And remember... Even if a machine made them, somebody still had to design them. Just cause they aren't made by some old guy huddling in a shed with a file and some emory cloth (from castings, by a machine! Gasp!) doesn't make them any less legit.
If paint needs to be sanded smooth, so does a 3D printed surface. I'm not saying it comes out horribly or anything, just don't expect a mirror polish....
Sadly I'm selling my GT Track Bike... it's a 1999 with the coveted triple triangle if anyone wants to scoop it up... size 53cm... Obviously you will have to PM me as we can't sell via the forums.