I don't think anyone can judge structural integrity by welding without taking in the whole sum of things. For example the Evolution, Mitsubishi's top end has its roof joined by just plastic screws, stamps and holders, not even welds, because it is near impossible to weld aluminium to the main steel pillars. Doesn't make it an unsafe car.

Welds also can be stronger than stamping depending on the way they're welded. If you go for an interior + long fillet, the joint can take even more energy than a normally cast or stamped joint. It all depends on the design.

TL;DR : TS is a moron.