Just to make sure that you realize I'm not ignoring what you said, I'll make these two quick posits...First, love can't be real without a choice in the matter, and that goes for Satan as well as us. He had to be given a choice, just as we have to. (Also, don't treat Satan's fall as something that happened in the past...time doesn't exist in the spiritual realm, it's a physical dimension only. We see the fall in Genesis, we see the fight continuing in Job, Daniel, the Gospels, and Revelation references it as a future event.) Second, I think you're confusing hardening (which is a strengthening of an existing resolve) with changing (which would revoke free will...something that we're allowed to have even though it can cause our own self-destruction).
But, I think it's important to remember some things. First, morality is separate from instinct (example-people will run into a burning building to try and save someone. Now, many believe that is a herd-instinct, but that instinct is in conflict with a stronger instinct for self-preservation. Something else other than instinct moved the needle to action-which we call morality). Morality has to come from somewhere, and religions universally examine that. Second, all valid questions must have an answer, whether known or unknown, must have an answer (Four types of questions are Farsical, which don't actually seek information and are therefore invalid, Fantastical, which use words/concepts that may or may not mean something to the asker and are therefore invalid, Wrong, which are based on incorrect observation but do have an answer and are therefore valid, and Right, which are based on correct observation and have an answer and are also valid). Science only answers questions of process and method, it is unequipped to answer questions of meaning (such as why). Philosophy attempts to answer the questions Science cannot, and religion is the branch of philosophy that addresses the meaning behind existence. Ultimately, there are multiple reasons to acknowledge that there is a God, and so you're left with the choice of what to do about that.