Laws are legitimate so long as people freely accept them. When the laws become oppressive, people revolt. Laws cement communities. People can reduce the number of laws, but must obey the existing laws. People generally observe legitimate laws even when there’s no threat of punishment. Legitimate laws can be arbitrary to a degree (a speed limit of 65 rather than 66 miles per hour), but are reasonable overall. A person cannot morally or legitimately refuse to observe a law, though he may campaign for changing it.
Jews may and should call for changing rabbinical observance, but as long as no new consensus has emerged, Jews must follow the age-old rules. Ancient people correctly equated antiquity with truth; the test of time is the only way to prove that a system works. The Jewish law, which preserved the Jewish people for millennia, is proven to work. Jews can keep changing it slowly, testing new laws, but cannot recklessly abandon it—or even worse, tolerate individuals’ disregard of the community’s legal backbone.