What is a community? A community doesn't produce itself. People produce a community. A community is formed by issues or matters concerning that people. The issues can be religion, a common history or a location. People can be connected by one or by all three. This is what forms a community, common issues that unite people.
When Allah says: “You are the best community evolved for mankind.” the word for best in Arabic is a superlative noun which means the greatest or highest degree of something. It’s not a comparison like good, best, or better but it means something that is elevated. You are the best in the history of the development and rise of communities, and that is life. It does not mean that the Muslim community is better than all other communities, it means the "best" that Allah created when He created human beings.
People enter into Al-Islam with chains around their necks or they were born into Islam with chains around their necks. Something is restricting their human potentials when they are pointing their fingers at others and everything is always the fault of somebody else. They cannot see the fault in themselves and that prevents them from progressing in life. Allah says: “He will never change the condition of a people until they change what is bothering their soul.” If you keep the soul pure in the human form that Allah created it in, it will influence the mind and the intellect to fulfil their duties and responsibilities.
When you become human beings in true form, you are in your original, human excellence, following the excellent urges, motivations and drives, and then you establish that excellence in a community life. You become the best group of people, the most beneficial people for humanity, the one that recognizes excellence in every action, by revelation or intellect, whether a Muslim or non-Muslim. They are the most read in understanding the meanings of letters and symbols and in understanding the grammatical language. They are the most regardful of the will of Allah, and the most commanding of what is universally accepted. They forbid what is wrong, unjust or evil, and they are most respectful of relationships, and obeying and trusting in Allah.