I never even heard of the website before but was able to find this statement by GD:
"In response to content complaints on the ar15.com website, our team investigated and discovered content on the site that both promotes and encourages violence. As a result, we informed the site yesterday that they have 24 hours to move the domain to another registrar, as they have violated our terms of service," GoDaddy told the Washington Examiner.
While trying to learn more about it I found that GoDaddy did the same thing to Gab in 2018, but that was a little different since it was response to a mass shooting:
"The platform made headlines in October 2018 after a gunman opened fire in Pittsburgh’s Tree of Life synagogue and killed 11 worshipers. Robert Bowers, who is accused of the crime, spent years posting anti-Semitic rhetoric on Gab. His final post before the shooting read, “I can’t sit by and watch my people get slaughtered. Screw your optics, I’m going in.”
There's obviously a trend going on right now but I'm guessing GD doesn't want another Gab situation on their hands either? I'm not familiar with any of these platforms getting banned/shutdown so I really don't know if they deserve this treatment. I mean, the Christchurch shooter in NZ live-streamed his massacre on FB and you don't see FB getting shutdown, but the shooter probably didn't use FB for anything except to livestream it.
I also tried visiting Gab .com just now and it looks like their site is down, or are they mainly app-based?