I don't remember when I specifically first heard D&D mentioned as being evil. In my youth I went to a "turn or burn" Baptist church. They may tell you it was something different, but that was the bottom line. I remember anything supernatural related being condemned, so I know D&D was lumped into that. I even gave up D&D for a while when I was in high school to better my soul.
I look back at those times with a mix of shame and laughter. Don't get me wrong, if you have faith, that's fine with me. Religion just isn't my cup of tea.