First it would cost a fortune for any Brand to do so. But I would imagine that if a seller is selling a harmful product causing major issues they do go after those.
But as the article suggests, suing is more harmful to the Brand than than not suing, at least en masse, as they have concluded that the PR in doing so, would or might cause consumers to reduce their purchases of the brand.
Besides, as you pointed out, European or foreign packaging and the look, composition of the product can very much be different. The EU might have prohibitions on certain chemicals, and color or texture preferences of a market surely can be different from the US.
We all know that there is a secondary market for just about anything made. From overruns, misprints, and even bad batches. The brands could be more transparent on that, but that costs $$ as well.
In the end, I am now convinced, especially after reading the stories of @ASV_Vites in regards to supplements that one is a fool to buy anything that goes in or on the body, unless one is buying direct from the Mfg or a legitimate retail chain