Sharon, I guess the theological and biographical implications of Newton and Amazing Grace are beyond the scope of this thread topic, but let me say this in passing.

It may be that it took Newton several decades to "see the light" fully (or as fully as he could manage for his time and circumstance). While I understand your discomfort, I can separate a song from the shortcomings of its author, especially if that author has been dead quite a while.

I think it's obvious that Newton reached out to God in the storm initially to save his own skin. I had thought that he gave up the slave ship business when he got back to port. Is that just one of those historical myths?

As for the song being about what God did for him, I just see it as a personal reflection on the New Testament teaching that you are saved by God's grace, not by your works. (Although you are also admonished to do good works, the Christian teaching is that it is not those works that bring about your salvation.)

FWIW, Newton's poem had a whole lot of verses (not including the "10,000 years" verse), and I don't recall whether any of the other verses said anything about repentance or atonement for his past sins.

"The song seems to be about getting a free no-obligation pass to heaven." Well, yeah, I guess you could interpret the NT that way, but salvation is supposed to involve repentance. I think it's understood that a person who truly accepts God's grace will not continue in the old ways as if nothing had happened.

"I guess I don't see as much inherent "merit" in the song as most people do." The question I would ask is, would you find the song acceptable if you knew nothing about the life of its author?   

To give a more recent example, I think the song "Tomorrow Belongs To Me" (at least the verses I've heard) is beautiful. I won't sing it, especially around Jewish people, because it was the theme song for the Hitler Youth. But, hypothetically, if I were asked to sing it by someone who had just heard it and thought it was a pretty song, and if there were no one around who knew of its history, I would have no problem singing it. (For the record, I don't foresee that situation occurring.)