How should Hindus treat people of other religions?
Hindu Dharma is non-exclusive. I.e it does not claim it possesses the exclusive right to grant salvation/liberation. It recognizes that every path can lead to the truth.
"ekam sat viprāḥ bahudhā vadanti"
-Rig Veda (Book 1, Hymn 164, Verse 46)
This means "The Truth is one; the sages talk of it in many ways."
Hence Hindus should treat others with "Mutual Respect". Note the word "mutual". Hindus should respect other's belief and their paths and also expect others to do the same to them. But this might not be possible with religions which do not offer mutual respect.
There is no concepts of False Gods and false prophets in Hinduism. It is more of a self-exploration of the mind(adhyatmik) than an organized religion. Hence the individual's experience(anubhava) is given respect, which again emphasizes respect to other religions. Though that does not prevent Hindus from engaging in philosophical debates with others. Adi Sankara is said to have vigorously debated Mimaamsa-vaadis & Buddhists. The debate is done with respect and not with contempt.
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