Wrong with this era? You mean during an era with the most athletic players and advanced defensive schemes, that have been built on the constant exchange of the offensive/defensive power struggle. Not to mention, the basketball public understands what constitutes as good defense a lot more than those during MJ's time in the league. I mean hell, even NBA coaches didn't treat defending the 3-pt shot seriously 25-30+ years ago. And what do you mean by "nobody on the GOAT list did it like MJ did"? Defense? Overall? Because LeBron has his measure in both categories.The turn this argument has taken shows what's wrong with this era. 90% of the conversation is about offense. MJ isn't the GOAT strictly based on what he would average in today's game or vice versa. Actually listen to what Ray Allen said. He listed passing as MJ's "weakness" (even though when he was put at point guard he ran off 7 straight triple doubles and 10 in 11 games) cause he didn't pass that much. He then said he had no other weakness in his game. NONE. MJ played defense. Offense will always shift and shape differently when eras change, but the concept of stopping the man in front of you doesn't. Nobody on the GOAT list did it like MJ did. He was the complete player that was great in every aspect of the game and it all translated into titles.
Not to mention if we're talking about "complete" player (not necessarily better, but fewer weaknesses/more overall strengths), LeBron certainly has a better argument.