Yes. "The argument contends." Because it is more precise and concise, "Proponents" is preferable to "Arguments in support of the hypothesis" and both are preferable to the vague and muddled "The theory". You oppose the change on the ground that "stupid" people might object to the article saying what the proponents' common argument is. I see no value of any kind in that contention. You oppose it on the ground that, until now, no editor has made this criticism of your writing. I see no value in that contention.