This is certainly not true.
Most researchers like a snitch when the snitch is right and successful. Especially when the crime is as severe as this one.
Or are you seriously saying that most researchers dislike people who find evidence of research fraud? That’s not my experience at all.
I do think that many academics unfortunately prefer conformists who do not point out bad research practices. But outright research fraud like the one described here is a different matter.
I'd recommend not to do anything. It never ends well for whistle-blowers. Can you name me one whistle-blower who is living a comfy life and has a good career? Exactly, there aren't any.
Blowing the whistle alienates the people you blow the whistle on and sends a loud and clear signal that you're trouble to all future employers. Nobody is looking for someone to challenge them and keep them honest. What they're looking first and foremost is a team player and a team player doesn't betray the team. You either voice your concerns to the team leader and you do so quietly and politely or you leave, but you never speak out in public against the team.This is how it is done. Make sure that the paper does not see the light of day, by asking a few annoying questions internally, but don't make a big scandal out of it.
Yes, you will be celebrated by the open science ppl but at the end of the day nobody likes a snitch.