If all your scammers are from one geographical location halfway across the world, it is fine to refer to it and you shouldn't be shamed for naming it. Lest we police ourselves into ignorance.
In the case of discussing LinkedIn, it doesn’t matter where the scammers are from. The adjective is redundant in this context.
In this thread, almost any other adjective would have allowed the main meaning of the sentence to continue uninterrupted (“filthy scammers”, “frustrating scammers”, “purple scammers”, “fearless scammers”). “Scammers” already includes a negative connotation. By adding a redundant adjective to an already pejorative noun, you run the risk of imparting some of that negativity onto the adjective as well. This easily leads to the perception of racism.
My point is that it's the same because the 'personal opinion/attitude towards certain people' is that all of them are Indian.
It's as racist as saying 'I'm sick of these Poles taking our jobs'. The truthful existence of Polish economic migration doesn't make it not a racist attitude.