I don't buy that. I find it hard to believe that a court could find that a slightly ambiguous clause means something so different from what the people publishing their code under it understand it to mean. If AGPL didn't exist, and if everyone using GPL claimed "convey" included a hosted service, then there'd be a case. But given that AGPL exists, and given that the intent of most people who use this license is not to prohibit hosted services, that's a major stretch.
Interpretation of contracts is not necessarily based on intent, especially if you're using someone else's contract, and especially if it's not a consumer contract (where, in many cases, a contract deemed to be deliberately misleading may not be valid).
