IMO, both were wrong, Pratik has this urge to rule the tasks no matter what. Karan has warned him after his first fight with Jay that do not mess like that himself.
Yes, it was weird, but it looks like, the violence scale is increasing with each season. There was a time, people were kicked out for abusing or just challenging someone for fight. Now WWE moves are acceptable.
As per preview, Pratik will fight with Jay again. That is who he really is.
In OTT, Pratik pushed Zee equally bad and should have been thrown out but BB played the game and saved Pratik. So same thing here, Pratik is aggressive and playing the same crap and Karan is more aggressive. Now, BB is choosing Karan over Pratik to stay and Pratik was also not thrown out after fight with Jay (the fight was more aggressive than Pratik - Zee fight) and breaking the glass.
So, both have been given chances on their aggressiveness. Tej will try to make sure that Karan does not do it but is not always feasible as she will be in opposite teams in tasks.
Why is only Pratik that everyone has issues. Food for thought?
BTW, BB is at the most fault also, making tasks with ambiguous instructions that promote fights and aggression. BB can clearly state that no one will take/tear/hide other people property but why cos deep inside BB wants these fights to happen. Another example of rules, Shamita can give as many canes to anyone and make a decision on a winner. So BB is more to blame than players.