The simplest answer to that is the one I gave to it a few posts up, and I shall recapitulate it briefly here. I encourage you to read the Book of Exodus of the Hebrew Bible for further details, but suffice it to say that the Jewish Faith is one that does NOT depend on revelation to ONE man, be it Jesus, or Mohammed, or Bahu'allah, or Joseph Smith, Jr, or anyone else. On Mt. Sinai, Jews received a NATIONAL theophany. Read through the posts here for more on that. But the entire nation accepted the commands of Torah. When the Jews at Mt. Sinai accepted Torah, they did it for themselves and all Jews past, present, and future. My participation in Judaism is simply doing my part in fulfilling my portion of the Covenant that my ancestors accepted on my behalf. We saw God on the Holy Mountain. He did the wondrous works in those days for all the Jews, not just one. I realise that none of this is going to matter to you, you will still say that my beliefs are silly, or illogical. I disagree. I choose the leap of Faith for one simple reason. I have seen too much in my life that is explainable in no other way.
I have had too much happen to me that shouldn't have. By all rights I should have died about eight times in this life. I should have had some other very horrible things happen to me that didn't. I believe that God is the only thing that prevented that. I choose Faith because no other explanation works, in my mind. My family is not, and never has been, observant. I came to observance on my own as an adult. There simply was too much for me to accept any other explanation. God was fulfilling His part of the Covenant. Why was I not fulfilling mine? That was the question I had to answer. And answer it I did, by choosing to fulfill my side of things. Its only fair. You may choose to disagree with me. You may choose to think I'm an idiot. But I ask you to respect my choice, as I respect yours. My brother and his wife are atheists to this day. But I believe, and I always shall.