I do find that kind of an odd statement. MJ is only 2 years younger than Anderson, Anderson's time was MJ's time.
I know it's odd, but it was said. Here's the exact quote, from Monday's Dayton Daily News article by Tom Archdeacon (the same quote, or very similar, can also be found on youtube, with Isaiah saying it on video):
"I would say before I knew about Michael Jordan, Dwight Anderson was the Michael Jordan of our era", NBA legend Isaiah Thomas, in a documentary on Anderson.
MJ was a late bloomer and his superstar reputation was built later, mostly with the Bulls. Dwight's was built in high school.
One high school All-Star game, held in Georgia, included Dwight, Isaiah, Ralph Sampson, Dominique Wilkins, Clark Kellogg, Mark Aguirre, Sam Bowie, Byron Scott and others (quite a list!). "Dwight dominated and was the MVP. Everybody knew him after that", said John Paxson. (also taken from Tom Archdeacon's TLTR DDN article).
Unfortunately he was pretty much just that: a high school phenom, that fell hard from alcohol and crack cocaine abuse, homeless for many years. A cautionary tale if ever there was one.