“However, I’ve always found that explanation to be unsatisfying”
Who do you think you are to find a maamer chazal to be unsatisfying? If they tell us the reason is so that the umos haolam cant say that they would have kept the Torah then thats it. Theres no questioning a maamer chazal. Only someone with a lot of chutzpah and azus panim would even think of doing it.