For the same reason people loved David Letterman for being an a$$hole, but the second James Corden or Ellen come under fire it's deavor season.
Most people (not including the bad faith social media clowns who paint everyone as their worst possible version) realize everyone's a mixed bag and they can be forgiving to a certain extent. But if there's one thing the masses refuse to accept from public figures, it's high levels of hypocrisy or phoniness, two traits which are ingrained in the DNA of the Hulkster.
We're talking about a guy who paid for the alcohol that crippled his son's friend, then blamed it on the victim because 'he was a negative person' all the while parading around like Joel Olsteen preaching religion wherever he goes. I wouldn't doubt that Flair is as morally bankrupt as Hoegan but based on public record it's not difficult to understand why their image isn't one and the same.
Also, this photo: