This wasn't a bad decision though, if you completely miss the ball with a slide tackle you're always going to liable for a yellow card and have been for a long time. There was really no need for Gnonto to be sliding around like that where he was in the first place, especially when he was already on a yellow.
If Germany lose this the players will never be let back in the country. It wouldn't surprise if they get a red card in extra time.
I don't think the referee was wrong to send Gnonto off but I also think it was harsh. I think the threshold for a red should always be high and I don't think he really needed to book Gnonto for that, even if he could probably justify it.
Germany really didn't create many chances considering they had a 2 man advantage for well over 30 mins.