My radio (accidentally) found a Christian radio station the other day and I was reminded that almost every time I tune in to religious radio or see some of the Christian TV adds, I want to change my religion to become Buddhist, Jewish, Muslim, Hindu - anything but what I'm hearing.
'Jesus didn't want to create an in-group which could banish others to an out-group; Jesus wanted to create a come-on-in group, one that sought and welcomed everyone' (Nigel Livingstone).
I’m not suggesting that all religions are the same and that it doesn't matter what you believe, that truth is relative; and I am not advocating a kind of "all-religions-are-equally-true relativist/pluralist tolerance. I am saying that because we are Jesus followers and because we believe Jesus is true, and that he accepts all people in love, kindness and grace, we should do the same.
Pharisees believed they were special, the elect, and the elite. They wouldn't associate in any way with non-Jews and they didn't understand the difference between acceptance and approval, so in case they be accused of approving of other religions they refrained from loving or accepting people who were part of other religions (as well as members of their own religion that they felt were sub-par).
To show love and acceptance of people is not to approve all they believe or do. To show disapproval of other religions, and belief systems by withholding love and acceptance may be orthodox Phariseeism and it may even be modern, Western, colonial Christianity; but it was not the practice, or the model, of Jesus Christ.
According to Macquarrie (Transforming Mission, p.483), there are seven formative factors in theology: experience, revelation, Scripture, tradition, culture, reason - and dialogue with other religions.
I consider myself a generously orthodox Christian; I don’t believe I am above Buddhists, Muslims, Hindus and others, in fact if I reflect Jesus then I am below them as servant. I am their neighbour, their brother.
Jesus didn't come to start another religion to compete in the marketplace of belief systems. If anything, I think he came to end standard competitive religion (which Paul called 'the law') by fulfilling it. Not, like too many religions, a place of fear and exclusion, but a place where everyone can find a home in the embrace of God.