Melodies have moved into Judaism from outside cultures since earliest days of the synagogue. You have heard the cantor and I complain in fact, about how some of the melodies our members hold most sacred, are themselves borrowed from Christian Church music or secular drinking halls. Jewish music in any particular geographical location, tends to mirror the music of the surrounding culture and its values. For example, when the bel canto, operatic style was in vogue in secular culture, then cantors who sang this way were seen as cultured and artistic. Now that this approach is out of style, a cantor who sings that way will often be branded formal or egotistical.
Music holds a special place in worship.
People will pick their congregation and service based on the music. For many Jews, who do not understand much Hebrew, the tune is the prayer. When the music is unfamiliar people feel that they do not belong. As a Hillel rabbi, this was a constant challenge for Summit, as every student walked in wanting to hear the tunes from their home congregation. It was not just music that was important, but the power of singing together.