From BLABBERMOUTH comment section:
I'm a friend of Dan Nelson and let me tell you some of the things that happened.
* Dan Nelson challenged the quality of the song writing when he became a member of the band. He did this in a respectful manner, but to his ears the new material was not as strong as previous Anthrax material. Only one who loves Anthrax dares to say this to Scott's face, but Scott being Scott wouldn't listen to the criticism. But actually the rest of the band supported Dan, but when push came to shove who do you think they sided with? The money of course. Dan said, okay, let's do it, and let's look forward to a brighter future, but the relationship between the band members had broken down, and Dan being Dan left the band. He might be a nobody but he has his artistic integrity!
Also, Scot's girlfriend became close friends with Dan. They both shared an interest in Egyptian art and several times they went to the Metropolitan Museum of Art in New York. Do you think Scott liked this? Of course not. He hated it.
I've talked on the phone with Dan today and he just wants everybody to know that he wishes Anthrax all the best. "Life has it's ups and downs, its dramas and fights, that's just the way it is."