Urdu is just associated with muslims because hindus cannot speak it, show me 1 hindu who speak urdu and i will believe you.
Only an Indian here can tell you whether the Muslims and Hindus of Delhi or Luknow speak two different languages. Language is more than a couple of hundred Arabic / Persian loan words. What about the syntax, verbs, grammar, the whole vocabulary aside from few Arabic / Persian loan words, proverbs used in daily conversation? Even after 67 years of immigration it is the Ganges which is flowing backwards in Karachi, and now even in Punjab and other areas of Pakistan where Urdu has replaced the native languages. Forget Punjabis, even "ahle zuban" pronounce many Persian / Arabic words wrongly and the usage of these words is anyway very limited in their daily conversation. You don't get to hear that Urdu laden with Arabic / Persian words on the streets of Karachi that you hear in PTV khabarnama or Pakistani soaps. Non-Arabic speaking Muslims can generally pronounce hard Arabic consonants because they learn to read Quran in the early years of their lives.