I have also heard the following:
We have to sing these songs because that is what the people who are not coming (and never came) want.
While we repeat lines seven or eight times, there are churches that repeat them more times than that.
God likes hearing the same line over and over.
Your music likes are just preferences. (I guess the worship leaders preferences are ordained by God).
Some other hymns older than that, dating two centuries ago, were written by John and Charles Wesley. Charles Wesley in particular received criticism of re-using the melodies of bar room jingles and putting Christian words to it. His idea, of course, was to make it so that if people heard the same song (without words) outside church, they'd think of Jesus and might be motivated to live holy lives instead of worldly lives.
Imagine what church music today would be like if the naysayers had won the arguments against the Wesley's and the Gaither band's influence.