It also focuses specifically on young cohorts so there are no people who loved in the closet for half of their lives. The range of medical transitioning described is by no means limited to surgery, and I don’t believe that therapy and hormones work differently in Finland compared to the rest of the world.
The primary takeaway here is that our understanding of gender and how to alter it is very poor and so treatment outcomes are often poor. That’s a call to more research and more efficacy, not calling trans people names and shunning them.
I understand why you’re defensive, it isn’t an unreasonable stance, but please do read the study at least.