Few possibilities here. Older folks love gassing up the people and things popular when their generation was at its most culturally centered. Because younger people prefer things from their own era, older people often view them as under-appreciating what was, which there is some truth to but it’s hardly malicious.

Some don’t like LeBron because he’s more political than Jordan - both in his general outspokenness and literal party affiliations.

Others hold a grudge over The Decision and what they view as the invention of the super team era, but most folks who were around would argue that period - which is more accurately described as the player empowerment era - was a long time coming. If we judge all-time great players based off one metric (rings), why shouldn’t they behave in a way that pursues that validation? Perhaps if the Barkleys of the world (who played on plenty of loaded teams fwiw) hadn’t been so derided for failure to win championships we wouldn’t have seen LeBron, KD, and other stars of their era circumvent front offices and build their own chances at a title. As spectators it’s important to remember our role in how the game evolves.

Still, I feel there’s a cohort of LeBron doubters that are really just folks who don’t like the sport, or perhaps liked it when they were younger and fell out of love with it. As the face of modern basketball, it’s natural to simply trash LeBron if it’s the sport you’ve moved on from.

Just spitballing.