Even though the sites may be related, they are not necessarily on the same computer, or web hosting company for that matter (a web host is a company that "hosts" or where the website content is actually sent out from). If the A & V site was on a particular web hosting company locatoin, and ForFMJbodiesonly.com is either in another physical location owned by the same web hosting company, or if it is on an entirely separate web hosting company, it probably won't get affected. Most attacks target a specific site.
The web hosting company itself may have been hacked, and A & V site could have been damaged as a byproduct of the attack in the web hosting company, or on a different web site that was on the same webhosting company/server as the A & V site. Usually, if web sites are defaced, and it is intentional, the attackers will change the front page to let the world know that they hacked the site. It has happened (a lot, the Anonymous attacker group being famous for doing it, as an example) in the past, but attacking a web site is usually a "for profit" case now. The attackers are usually looking for immediate gain (credit card numbers, bank account numbers), or longer term (personal information, potential embarrassment material (i.e. the Ashley Madison data theft)).
No way to know for sure without looking at the system log files, but I would suspect that the attack that took out the A & V web site was not targeted at the A & V website, but was collateral damage. It does indicate that the web hosting company does have security issues.
