Answer: Because not only to perform them, but even to receive the Torah, we must be “as one person with one heart.” How can we say today that we are fulfilling the laws of the Torah?! We first must yearn to attain the conditions for their implementation or at least yearn for unification. And then we will find out that all the laws of the Torah speak about how to attain unity.
Receiving the Torah is only the beginning of its fulfillment. After having received it, egoism begins to be revealed more and more and we must increase the unity between us. That is how our common heart grows until it will include everyone within it.