I don't think I understand what you mean, the "not particularly dangerous" comment was in relation to the vulnerability that was found right ? Surely they would know what constitutes a lower severity level.

The "not particularly dangerous" is a headline for a section talking about Mythos, not the vulnerability.

My guess is that it is in category of "you are holding it wrong". Still worth fixing, but requires very specific user input for example. Or very weird scenario. Or in some less used protocol or flag combination.