The answer to this question is simply Free Will. (not the same as Free Willy, which was a movie-joke) God is awesome, real, slow to anger, kind, merciful, (his mercies are new every morning) and ...what I have personally found out, - friendly, and not just friendly, but He is the best, best friend -ever!
Explanation of how God and His Revelation (the Bible) fit together, and fit into our experience in life, is as follows. Nutshell Version;
God is kind, tenderheart, all the 1 Cor. 13 description of Love, Personified,..and He does Good only and consistently.
He is all powerful and omniscient, but has given us free will to make choices, therefore we can choose to disobey his rules, (to our own detriment because breaking rules has built in consequences.
Lucifer, who exalted himself through pride and fell by it, taking one third of the angelic realm with him, took the earth and the dominion of the earth away from Adam and Eve, in the garden in the beginning. Jesus came to buy back, and redeem all that was lost in the original fall, including the earth and the dominion of it, for man. Jesus gave this back to us, as Adam and Eve's descendants.
Lucifer's method operendi is to 1-steal, 2-kill, 3-destroy, as it is written in the NT. Whatever your losses in life, whatever has been taken away from you wrongfully, stolen, whatever has been destroyed, ie. relationships,.etc., or illnesses, maiming, diseases, financial losses and disaters, debt, etc. are all due to Lucifer's influence on this planet,
@Hello You've just passed the buck. Now the question is Why doesn't God stop Satan from doing all this evil? Actually, the question remains "Why is there evildoing at all?" Who is doing the evil is really not important unless the claim is that God cannot stop those doing the evil.
