It’s a little difficult as we can only talk about our own pigment with any authority. We are not experts on the pigments used by others.
This said, I think that ‘blaming pigments’ is an easy ‘get out’. The truth is that they are often very basic, derivations of tattoo ink or cosmetic pigments. Some are more suited to scalps than others and our research has led us to develop and use one that we feel is most effective.
The news piece aimed to straighten out a few misconceptions about discolouration and migration. It was written because we were seeing a lot of misplaced panic about pigments.
It is worth looking around, forums are often useful and Scalp Guru has some degree of independence. I found this piece there earlier: https://www.scalpguru.com/scalp-micropigmentation/research/discoloration/
We are happy to divulge details of our own pigment at the consultation stage. I hope that helps but please do not hesitate to ask other questions.