FTR, I do get why he irks people. He irks me, too. It's not all love from me, even though he's among my favorite players all time.
I do think he is fake. All players have to be a little fake, but he's above average (and it makes sense for him to be, but it still bothers me). I hate the ref manipulation, but also, who doesn't do that? Everybody, even in the 90's. Even MJ. But Lebron does it a lot, especially pretending he's hurt after a hard foul. I just grew up thinking you leaked weak if you showed you were hurt. He does it to curry favor with the refs and it's a winning strategy, I just don't like it. He has some poorly though-out political opinions, which puts him with basically every other sports star, so I don't see the big deal.
Because he's so good, he will be hated of course, but the level of hate goes way beyond matching anything he's done to merit it.
The key is that there was this "golden age" of athletics that guys like LJ are compared against (probably unfairly).
The 1980s/1900s gave us a lot of great athletes we wanted their playing cards for. I am going to use Football since I know it best but same could be said for NBA, MLB, etc.
As great as the players are today, people still look back at players like Joe Montana, John Elway, Dan Marino, Jerry Rice, Barry Sanders, Emmitt Smith, Troy Aikman, Steve Young, Eddie George, etc. Something about that era produced very likeable and impressive athletes across the board. It probably helped that politics was a lot simpler and the economy stronger in that era. Ironically, we may have better players today but it seems like most of them don't stack up to these "greats" unless they are Tom Brady level.
People still remember the NBA era of Michael Jordan, Magic Johnson, Larry Bird, Charles Barkley, Isaiah Thomas, Clyde Drexler, Shaquille O'Neal, etc. as the greatest era just like the NFL era that I listed above with the 49ers/Cowboy dynasties.
I can't 100% explain it but none of the athletes since tend to measure up to this era even though I think the teams and athletes are just as good today. There is just this magic nostalgia around it.
One of the largest arguments around Lebron (whether or true or not) is that he didn't play in the era of the dream team and Jordan did (i.e. Jordan played against better competition). This tends to be the case across the board and not just the NBA.
We still rave about 2001 Miami and 1995 Nebraska. 2001 Miami would likely get beat by 2-3 TDs by 2022-2023 Georgia. The level of play in college (especially on offense) has improved dramatically. What teams like Miami and Nebraska had that helped them in their era are pretty widespread around the sport now and has been improved on.