This is, I hope you would not deny, largely due to the Hindu tradition of accepting that no one has a monopoly over truth. Which is why I am rather disappointed that even a person like you, coming from a sect that has some connection with Hinduism, keep saying that Islam is the only true religion.
I would deny. In fact I have always thought Hindus have forgone the caste system of their vedas when practising democracy in India.
Pakistan was created as a secular state but has over time been taken over by a "caste" system of religious fanatics. India, however, was ruled by those who believed in the Vedas and who believed in a system of Brahmans and Shoodars but who implemented a far more secular system than their belief. India did a better job due to this. Thumbs up. I am saddened how my country has failed in this regard.
As far as respect for religions is concerned the Vedas contain no such thing and the Vedas form the core of Hinduism. The Gita also, I believe, does not say such a thing but I could be mistaken in this regard.
Still, even if I am mistaken, the respect Islam gives to the Prophets of other religions (such as Krishna) is unparalleled. We are not told simply to respect. Rather we are instructed to BELIEVE in all the Prophets of the past and to believe in the truth of their original teachings. And if we do not believe in their truth we can not be called believers. Belief in Moses, Jesus, and all is an article of our faith that Muslims can not bypass. Hinduism does not come close to this teaching of respect and love and devotion for the founders of other religions.
So yes, I strongly disagree.
I am impressed by your optimism and attempt to unify mankind by stating that many religions are in one way or another true. But unfortunately this belief does not have foundations on rational thinking. There are fundamental contradictions between religions today that could not have originated from the same God. While similarities exist in many teachings those similarities are explained in Islam as resulting from the Divine origin of all such religions.