That seems like, uh, motivated reasoning. Maybe if it were "for even a rich man" or "for a man, rich or poor," or something, but it's pretty clearly positioning riches in contrast to entering heaven.
If I understand correctly, at that time, riches were viewed as a sign of God's blessing. So it has the direction of "even those of you most in God's favor can't enter the kingdom of heaven". Which gets you back to something close to WalterBright's interpretation.
The interpretation I quoted came from Google. I did not make it up.