Very simple, it wasn't a missile launch. I have observed missile launches off the California coast multiple times: (1) the angle was too low; (2) the supposed missile did not accelerate in the manner a normal missile accelerates; (3) subsequent video of the contrail demonstrated a largely horizontal vector.
End of story.... The very concept of missile conspiracy theories is laughable. Believe what you want to believe and then call it the truth just don't make it so.... Brig. Gen. or Col. Sanders