>>> So, court decides to hang a guy and then public protests. Based on the protests, court reopens the case, retries the fellow and commutes the sentence and even lets him go free. That indicates the court and judges are senile, and you call that a perfect legal system.
Suppose people had not protested the earlier decision of the court - the guy might be hanged by now based on the first decision of the same court. So much about your defense of the legal system, judges and the court!
I'm not claiming our legal system is perfect but it still provides sufficient checks and balances so bloodthirsty mobs don't get the lynching they so much lust for. If you were unjustly accused of some heinous crime and sentenced to death, I think you'd appreciate these checks and balances much more.
>>> In stead of blaming the mobs, you should be blaming the legal system and court which sentenced the guy to death in the first place.

>>> He does not want to scare the perpetrators with that type of tough talk -- catching them and punishing etc. So he is calling for something else.
Communal harmony is better served by not allowing this type of attacks to occur in the first place with such frequency.
That serves his point - to sound credible and be seen doing something.
He probably knows that he (police) won't be able to catch the perpetrators, so he skips the tough talk on them (catching and punishing part). That makes him credible for later - nobody will be able to hurl accusations at Govt. when nothing happens (catching the guilty etc.).
On the other hand, everyone (including the PM) knows that public more or less will stay calm (in spite of a few grumbling here and there) – therefore the talk on "communal" harmony is safe and sure. It also makes the govt. look like as if it is doing something (making noise at least) and that the things are working because of Govt. (i.e. public is calm).