I personally think it’s a couple things.
3. That contact hurts more than you think
These are just theories of mine though, because I’ve never played soccer at a high enough level to know.
Some of it is flopping to draw attention to fouls. The center ref is sometimes 200’ from the contact.
But the story I always tell is my son got his hand broken playing soccer once, just but the ball being kicked into it… and that was in 6th grade. It’s hard to describe the power in the legs of elite players.