[Facts] Are Micah and Michael related?
They both mean exactly the same thing.
Replies
It is the same Person, true,* but the former is (an estimate of) His proper Name.
I can refer to you as Anthony or the OP (of this thread). Both are correct and identify the same person, but they are semantically different, a valid distinction in etymology > onomastics.
*Your point is valid in a Theological discussion, but these discussions are linguistic in nature.