But how the hell are they saying “forced” to do something by some scumbag over the internet?

There was a group from Brazil doing stuff like that and got publicized when they were arrested recently. Usually they'd coerce the minor into sending one picture, then use it as blackmail against them to give them more. They might even gaslight them to convince them that they'll get in big trouble if they tell anyone and it'll just get worse for them.

I've seen full fledged adults taken hard by scammers and willingly giving them thousands of dollars against their own interests, and they heavily distrust and resist anyone trying to help them. I can only imagine accomplishing that with a child that lacks long term thinking skills is even more effective.