The way contestants have treated her is not right and is a sad reflection on their attitude. I will agree that as a singer Asma is the weakest. She has a lot to improve. Everyone has a complete right to give her a tough, strict but fair criticism of her. However, instead of objectively critiquing her singing they are attacking her personality and nature. People are making fun of her poor Hindi and off beat humor. No matter what no one has a right to make fun of her or insult her. It is one thing to provide objective criticism and another thing to humiliate someone.
To give Asma due credit, it is not easy to sing in a foreign language you are not familiar with. Singing is not just about voice and melody, expression plays a key aspect too. Songs evoke moods like romance, exhuberance and other emotions because singers understand words and reflect the mood and emphasise words. Singing in an unfamiliar language has the heightened challenge of trying to be emotive in the vocals.