I don't think there is any issue with what Siggery is doing. It's first worth noting that copying of guitar shapes has always existed and that the market for Siggery is not the same as BM or BRJ.
Siggery is making guitars for the people that can't afford a Bernie Rico Jr. or BM. His guitars are not of the same caliber because of that reduction. Different markets, they are not likely to tread on each other. He also never claimed the shape was his, sure he gave it a different name but far from claiming it's his.
IDK if it's people that are just upset to see lower price copies of their favorite guitar. Or if this is somehow in the same league as that company, Blackhart (or whatever it was.)
In the end, I an get a BM shape with out Doug's bullshit marketing mindgames.