Has religious dogma been used competitively?

The only information I had obtained about a major institutional religion using its apparently newly-created dogma as a tactical ploy against another institutional religion is as follows. I read (details of source and author now lost) is that some time in the past –perhaps during the anti-Jewish policies in Europe – the Christian Church let Judaism, its parent faith, become aware that the Messiah had already come and gone; and that He could not appear again as He now was with God (and is also of God).

If this report is true, why attack another religion’s core belief, especially the religion from which it had arisen? Was dogma used to undermine another religion? If so why?

My first experience of dogma being used as a competitive recruiting (conversion) tool occurred a year after my arrival in Australia. Before that, a university tutor friend had invited me to convert to Christianity. I then told her about my religiosity back home. Curious, I asked how my behaviour and underlying values would change after adopting Christianity. She took a week to think about my question. She then said that, since I would not need to change in any manner, there was no reason for me to convert. That was that.

However, the next year, I was approached by a young man dressed in black, with a touch of white at the collar. He offered ‘salvation’ by conversion – a nice display of divisive dogma!

Not being aware then of the bitter divide between Roman Catholics and Protestants, I saw this man as some sort of well-meaning but very intrusive and insensitive priest. I had just told him (at his request) about my religiosity as a Hindu. His explanation for my conversion to ‘the faith’ was my ‘salvation.’

What is salvation, I wondered. Changing religions was also a strange concept, since my family’s close friends included Christians – Church of England, Presbyterian and Catholic. We all knew that, while we were on separate paths, they all led to the same destination.

Are Asians more tolerant than Europeans of religious differences, ignoring any dogma intended to divide humanity?