Ethics and security
Actually, not everyone in the AV industry believes that creating replicative malware for restricted purposes under controlled conditions is automatically unethical, and the fact that some researchers decline to do so doesn't give you the right to assume that they couldn't if they considered it appropriate. Here, though, the point that's -already- been made very clearly is that there is no absolute technical reason why this particular test had to be carried out using replicative software.
The actual nature of the ethical objections comprise one of the many issues that the industry hasn't succeeded in communicating very well, though individuals have tried, strenuously, many times. But is it worth it right now, given the anti-AV prejudices on display here?