Mahatma did the mistake of accepting the partition in the name of religion. and icing of the cake was to accept allowing the muslims to stay back in India making the whole reason for paritition itself meaningless.
It is as good as carrying the pot from well and breaking it at the doorstep.
I condemn Killing of Mahatma or any human being , but you have understand the feeling of those people at that moment, shocked by the decision of Mahatma allowing partition.