I thought about your response, as it was well-worded and you had obviously done some thinking before you posted. However, I have to disagree with you: God's love is NOT unconditional. Yes, God makes the rain to fall on the just and unjust--but not forever. "My Spirit shall not always strive with man." Your take on this also leaves out that God caused the rain NOT to fall on some folks when Elijah prayed. If God's love was unconditional, why would He do that?
The word unconditional means 'without condition'. Suppose you and I entered into a contract and I agreed to send you 50 dollars a day. Now, if I set a condition--"But if you behave badly and don't show respect for others I will cease sending the money to you." Then that contract between us is conditional. I would be agreeing to send you money on the CONDITION you behaved well. However, if I just chose to give you the money, with no requirements on your part, you would be free to go out and act any way you pleased toward others, and you would still keep getting the money UNCONDITIONALLY.
This is what you are saying God does, but you turn right around and contradict that position by saying that some faced God's wrath and died in the desert. The problem in this position is one that addresses another common misunderstanding: what love truly is. Most assume that, in order to be love, it has to go along with anything a person does. But we don't apply that kind of illogic to our own earthly parents--so why to God?
The word for God's love in the New Testament is 'agape' and it literally means 'a sense of social and moral RESPONSIBILITY'. It is NOT feeling based. Feeling based 'love' as described in the New Testament is the word 'phileo', and it is man's love. Unredeemed human nature is such that it desires to sin with impunity (no fear of any consequence). However, God has set up the universe in such a way that sin, like mitzvah (good deeds), is its own reward (although the rewards are very different).
So God's love is agape--based on getting us to the best moral and socially responsible place possible. Which is why His love CANNOT be unconditional. He deals with us on a BEHAVIORAL BASIS for OUR MORAL AND SOCIAL BETTERMENT. That is conditional, the very definition of it. And He gives us the same right: "Love your neighbor AS yourself" (not more than: not less than). This means we are not obligated to do more for a neighbor than we would expect done for us. So, if we do, it is through our MERCY, or GRACE--unmerited favor.
Which is what God does when the rain falls on sinners (although in some cases it may just be God sparing the righteous suffering, not the sinful. Recall that Sodom was spared until Lot left the town for LOT'S sake, not the Sodomites' sake). However, scripture tells us not to presume on God's grace (keep me back from the sin of presumption). Why? Because if an evil heart of unbelief is found in us, Paul says we can expect to perish as those you mention above.
So grace is given to us freely, but not unconditionally. Just as in the example above, if I gave you money and expected no repayment, but made the condition that you had to do well in business, then you got the money FREELY, but NOT UNCONDITIONALLY. And since God requires of us certain things after giving us the free gift of salvation, then He cannot be said to be giving us grace UNCONDITIONALLY.
Freely, yes: it is totally without cost to us, since Christ paid the price on the cross. Unconditionally no: we are told "See that ye refuse not him that speaketh. For if they escaped not who refused him that spake on earth, much more shall not we escape, if we turn away from him that speaketh from heaven".
The problem lies in so many using the two words-'unconditional' and 'free'-as if they were interchangeable, but they're not. That and a basic lack of knowledge of what the Bible says God's love is. We have this passed on to us by teachers and preachers, who really ought to be studying this stuff out for a true understanding of it before trying to teach the wrong thing.
Like scripture (which mirrors life itself), this issue is much more complex than we've been falsely led to believe.
It's just so much easier to trot out a one-size-fits-all sound byte for folks than to 1) Do the work yourself so that you know the biblical teaching on such things and 2) Invest the time and effort it takes to answer people correctly so that their faith will be sound--and by taking the time to do this, we are fulfilling the Bible's definition of agape by showing a sense of moral and social responsibility toward our neighbor.
Hope this helps clear things up a bit for you. :-)