Unfortunately, the expansion of religion has been used as justification of forced conversion and even genocide. Perhaps the memory of conquering the New World and subsequent genocide of native inhabitants, in the name of conversion and "saving" heathens has slipped through notable history, but the same was done in southeast Asia, Africa and pacific islands. The problem isn't the religions, the problem is the use of religion as an excuse for conquest, subjugation and ultimately the accumulation of wealth and power.