No different than US basketball players hamming it up and falling down trying to draw a penalty for the opposing team.
There are real, very painful injuries in soccer, there are 10 at this link:
http://www.tsmplug.com/news/worst-injuries-in-football/
I agree. Soccer is a demanding sport, and I have to say that anyone who honestly thinks otherwise is just not appreciating the realities of the game. During the World Cup many players ran the equivalent of a 10K each game, excluding overtime. This, in a tropical climate. Yes, flopping is a problem, but there are real injuries as well, and what happened to Neymar could have easily led to permanent paralysis.
Everything has to be considered in context. Lebron James is 6'8”, and 250 pounds. He's a great player and no one in their right mind wants to get in his way when he's got momentum going to the basket. Still, he had to come out of an NBA finals game because he was dehydrated and overheated. Does that make him weak? Of course not. My point is that ‘toughness’ includes lots of different parameters, and soccer players deserve their due.