First of all, MJ put up huge numbers against every team and every race of player (im assuming you're posting this because they're white) he played throughout his career.
Secondly, that was the best frontcourt in NBA history. Parish was 7 foot tall , Mchale was 6'11, Bird was 6'9 and half. Parish and Mchale were very good defenders and Charles Barkley even said he had his toughest games against Boston and Mchale. And we all know how strong and athletic Barkley was. They also had 6'11 Bill Walton coming off the bench in addition to Dennis Johnson , another very good defender guarding Jordan on the perimeter.
Thirdly, this is from the 86 playoffs. In the second round of the 86 playoffs, The Celtics faced the Hawks and Dominique. Nique was the type of player who could do things like this :
For sure one of the most athletic and strongest players of all time and in that series, he had 24/6/4 on 39FG% against the 86 Celtics. According to basketball-reference, The 86 Celtics were one of the best defensive teams of that era.
If you think just being strong, explosive and athletic is enough to have big numbers against that team, you're either stupid or have never played basketball before. Jordan was able to do it because in addition to being all those things, he was also the best midrange shooter of all time. If you watch the game in which he had 63, most of his points were from midrange shots.
That was an era in which teams were allowed to be very physical and the paint was clogged making it much harder to penetrate to the basket, unlike todays NBA were the paint looks empty. Just because the players on that Celtics team look a certain way doesn't mean they couldn't shut down athletic players.
Lebron won't average more than what he normally averages against that team. Hell, considering he was shot down by an average defensive team like Dallas, he might even average worse and shoot a worse FG%