THAT is an excellent question! Thank you. There are several arguments about why Jews were given the Torah, with its 613 Commandments, vs non-Jews, with the Seven Laws of Noah only.
Essentially I think it comes down to the following:
Observe:
1. God created man. Man then fell, and was kicked out of Eden (however you wish to interpret that, literally, metaphorically, etc).
2. God saw that man became so evil that he destroyed most of us. Noah and his family lived, and God swore never to destroy man again. He blessed man through Noah, and gave man universal laws.
3. But man could not even keep those laws. Man continued to fuck up.
4. So this time, God decided to have a special nation. He started with Abraham. Abraham was given two children. One was promised a nation, but not land per se. The other was promised a land, namely, Eretz Israel.
5. The Hebrews, even with their own nation, STILL were not faithful to God. So God gave them more and more laws to make them a people set apart from others. By doing this, by making us more obedient, he defined us further as a people, as a nation. Jews became distinctive. By making us a people set apart, he assigned us a special destiny. Just as he gave us a priesthood (the Cohanim and the Levites) to serve the Temple, so did he make us a Priesthood, a Holy Kingdom unto the nations. But just as the Cohanim and the Levites have more commandments (ie, some of the 613 apply only to them and not to the rest of us) to follow than other Jews, so do Jews have more commandments to follow than other persons.
This is the best explanation I have for you. I don't know if that satisfies you or not. But there you go.