Probably at least in part, but there was another dynamic going on at that time and afterwords, and that is the "building the fence around the Torah", which toughened up some of the Laws because there's a human propensity to fudge a bit. Now, whether these provisions are actually all included in the oral law supposedly dating back to the Sinai Experience is rather conjectural.
Jesus appears to be taking a "liberal Pharisee" (sometimes referred to as "love Pharisees") position whereas "love" dominates all of the Law. Therefore, to Jesus, if one follows the "law of love" all the other Laws are basically covered. Obviously, and for good reason, the vast majority of Jews disagreed and still disagree with that approach, although we fully realize that compassion and justice permeate Torah, Tanakh, and Talmud.