I work in the field, so unfortunately, the photographer is "right" in terms of his intellectual property rights. Took me awhile to learn some years ago, but the production & media field is super locked in with rules and legal regulations, that don't care if you're Lebron or complaining on a message board.
Here is what it is:
Most photographers or anyone are excited to do anything, especially for a rapper or athlete, plus they just pick up cameras, get paid, and shoot.
Real photographers, and likely this guy, eat off the initial gig, but eat for life off of the photos, and yes, they own the photos, unless they signed their rights away, which real photographers almost NEVER do, unless you pay a very large sum.
The reason media is lucrative (music, photos, sounds, etc.) is because you get paid to create that "art".
Now, if you want to use my photo on your website because it's awesome, you have to pay a fee. It's a licensing fee, and it last for as long as you set it up to be - but once it's over (unless lifetime), you can't keep using that image. Also, if you want to use my music/photo/etc in a magazine, it's another fee. Social media, another. A commercial, a movie, a ad, all fees.
Now you can see how iconic photos (and music, etc) set a photographer up for life, and it's only fair.
Also, you have some photographers/musicians etc that are super serious about their craft, and don't really care who you are, they are more in the craft then the business of celebrity. LBJ probably got that photo sent to him or shared, and he posted, as he always would.
The photog probably is wondering how he got the photo, and now, since LBJ posted it, he can no longer license it, because the world has it and will do as they will with it - the value has went down.
So, he is using the LBJ brand/business/LLC (not LBJ himself likely, since major artists and athlete brands are businesses) for IP lost earnings.
Like I said, maybe I wouldn't have done that, but I def know people and work with people that would, because they can eat elsewhere. This dude may not be just an NBA photog, and only cares about his art and earnings.
Just a learning lesson. And if, like someone said above, LBJ cut out the watermark or name, I can see some of my media people not going for that.
Also here is a lesson that may hard for the general public to understand:
Just because someone takes a photo of you, or interview or audio or whatever, does not mean that you own it. You have no legal rights to it, unless it was taken without your permission under secrecy. This does not go for athletes and entertainers in their job setting, politicians, etc. You can't do an interview, not like how you are portrayed, and demand it to come off the internet, for example - that company owns the rights, not you.