In my experience, it's pretty common in India for religious and political leaders to say things such as how all religions are the same or how Shiva, Krishna, Allah, and Jesus are all the same God. I know of Hindus that have no problem praying at churches, mosques, gurudwaras, and other religious places. However, while it seems that many Hindus accept that the Gods of all other religions are the same God, I don't think a lot of Christians and Muslims are buying it, aside from a few liberal sects like Ismailism or Sufism. Another example I can think of is the saint, Shirdi Sai Baba. He tried to bridge the gap between Hindus and Muslims and he practiced a form of Hindu-Muslim syncretic religion, yet if you look at Shirdi Sai Baba's followers today, the vast majority of his followers are Hindus and there aren't many Muslims that accept his message.
Of course there are some exceptions. In my Hindu tradition, those that come from Muslim or Christian families (who make up merely a tiny minority) aren't required to stop going to the church or mosque. In one of the...sermons(?) I guess, one of the swamis was talking about a devout follower who came from a Muslim family and would visit the temple frequently, but they never stopped him from being Muslim though. He would pray at the temple, while also doing his namaz five times a day. For the swamis in our tradition, that was something to be proud of. Interestingly, typically in my tradition, Muslims, Christians, or Parsis that come pray at our temple aren't considered Hindus, but they're merely called the Muslim devotee or the Parsi devotee, despite them praying at the temple.