I disagree with your argument. As per my prior post, Merriam-Webster defines snarky with crochety. So, yes, that is part of the official definition.
In addition, a list of accepted synonyms is not making up a connection where none exist.
Third, I don't think an argument on semantics is really necessary. Snarkiness is one of the most common behaviors that is considered a violation of posting on many forums. Rv.net is no different. There is nothing funny about snarkiness - it is not a joke when it is said, although many posters will try to claim "I was just making a joke" when they get called on it.