A possible answer to this stems from the anthropic principle. We evolved in a place with a moon because the moon helped us evolve. We don't see no moon because complex life such as us would not have developed without it. A stable rotation and gentle tide are conducive to the evolution of complex organisms; tides were instrumental in getting life out of the seas and onto land.
"Why is the sun the way it is?" can be answered similarly. A smaller star has too small a habitable zone where liquid water can exist. A larger star would have burned out sooner than the 4.5 billion years it took to develop sapient life. A double star has a much smaller set of stable planetary orbits. That the sun is an appropriate star for our life on earth is not divine providence or an enormously unlikely coincidence; it's the result of a universe-wide scenario of statistical multiple endpoints.
totally agreed with you up to that point which I have hard time understanding.
so you say universe is kind of fractal and we happen to be in the right place on that fractal, where all the ingredients come together?
'How' asks about the current state of things and how they are possible.
'Why' asks about the past, and how the current state of things came to be.
Depending on interpretation of the question, 'why' can be a lot more philosophical than 'how'.
Science doesn't really aim to answer the 'why'-questions, but rather the 'how'-questions. The scientific method boils down to falsifying hypothesis, and it's a lot easier with 'how does the tide work?' than 'why does the tide work (the way it does)?'.
Science can't say anything about 'Why does anything at all exist rather than not exist?', because there is no way to test any of the answers. So it's left to mythology, religion or philosophy to answer.