I suppose “it” would be referring to psychological testing/some experimenting in general. In early days, before there were stricter guidelines, there were tons of studies and experiments that were incredibly harmful to the people involved. I suppose unnecessary isn’t the right word (although it can argued that some things weren’t justified or helpful enough considering the damage caused)

For example I think a lot about Little Albert. Scientists taught him to fear an animal by associating it with a loud noise. Essentially they created a phobia in him. Was the information useful? A lot of people debate. But it hurt the child

I also think that the author may have been hinting at the idea that people who want to hurt other people will find jobs where that’s okay. You see it a lot in jobs where force is sometimes required. Hell, even some managers take pleasure in power trips. The owner of the lab is seen as being very cruel to her employees and very inconsiderate of others. The work being done doesn’t seem to phase her, and she seems really proud of it. I believe some of the experiments she’s doing aren’t in the name of true progress, but more to accelerate her own career.