As an Agnostic i see these verses as Islams equivilant of Excommunication. it's the Big Stick.
Although Yaweh and Allah are oft forgiving and merciful, theres a cut off point a "mortal sin" which will forever lock you out.
Catholicism lists the sins, and they tend to be things that would break the faith, such as denying the Holy Ghost, or disbeleiving that Jesus jumped into a cracker millions of times every sunday.
Islam 's verses are more subtle. Only Allah knows the criteria for being locked out of paradise and its up to him alone. This can potentially lead any action of the person to being punishable with the ultimate sanction.(apart from immediate divine intervention causing death).
Obviously as agnostic, I veiw it as a control mechanism, but appreciate its subtlty and open-endedness.
Why would Allah want these really bad people out of heaven, even if they repented? Well it appeals to the sense of justice. Most people would want paradise to be free of those who had done truely evil acts. You might not mind meeting a reformed con-man in jannah, but to meet the murderer of your father?

i don't see how you make the connection between the two, as "Qur'anic Justice in not posed like others. consider this story in Surat Al Kahf:
Muhsin Khan: And put forward to them the example of two men; unto one of them We had given two gardens of grapes, and We had surrounded both with date-palms; and had put between them green crops (cultivated fields etc.).
33:
Muhsin Khan: Each of those two gardens brought forth its produce, and failed not in the least therein, and We caused a river to gush forth in the midst of them.
34:
Muhsin Khan: And he had property (or fruit) and he said to his companion, in the course of mutual talk: I am more than you in wealth and stronger in respect of men." [See Tafsir Qurtubi, Vol. 10, Page 403].
35:
Muhsin Khan: And he went into his garden while in a state (of pride and disbelief) unjust to himself. He said: "I think not that this will ever perish.
36:
Muhsin Khan: "And I think not the Hour will ever come, and if indeed I am brought back to my Lord, (on the Day of Resurrection), I surely shall find better than this when I return to Him."
37:
Muhsin Khan: His companion said to him, during the talk with him: "Do you disbelieve in Him Who created you out of dust (i.e. your father Adam), then out of Nutfah (mixed semen drops of male and female discharge), then fashioned you into a man?
38:
Muhsin Khan: "But as for my part (I believe) that He is Allah, my Lord and none shall I associate as partner with my Lord.
39:
Muhsin Khan: It was better for you to say, when you entered your garden: 'That which Allah wills (will come to pass)! There is no power but with Allah '. If you see me less than you in wealth, and children.
40:
Muhsin Khan: "It may be that my Lord will give me something better than your garden, and will send on it Husban (torment, bolt, etc.) from the sky, then it will be a slippery earth.
41:
Muhsin Khan: "Or the water thereof (of the gardens) becomes deep-sunken (underground) so that you will never be able to seek it."
42:
Muhsin Khan: So his fruits were encircled (with ruin). And he remained clapping his hands with sorrow over what he had spent upon it, while it was all destroyed on its trellises, he could only say: "Would I had ascribed no partners to my Lord!" [Tafsir Ibn Kathir]
43:
Muhsin Khan: And he had no group of men to help him against Allah, nor could he defend or save himself.
44:
Muhsin Khan: There (on the Day of Resurrection), Al-Walayah (the protection, power, authority and kingdom) will be for Allah (Alone), the True God. He (Allah) is the Best for reward and the Best for the final end. (La ilaha ill-Allah none has the right to be worshipped but Allah).
the one man, the disbeliever. got:
1) NOT 1, but 2 gardens of grapes! AND
2) both surrounded by date palms! AND STILL
3) green crops put between them AND ADDITIONALLY GOT
4) a river that gushed forth right smack in the middle of them!
(what a punishment!):blind:
what did the believer get? let's see:
we're NOT told, BUT he had faith!
"But as for my part (I believe) that He is Allah, my Lord and none shall I associate as partner with my Lord.
It was better for you to say, when you entered your garden: 'That which Allah wills (will come to pass)! There is no power but with Allah '. If you see me less than you in wealth, and children.
the "poor man" was the richer of the 2, for those that have "eyes to see."
EVERY GOOD THING given to the first man, in terms of wealth BLINDED him to Allah[swt] and to justice!
the poor man, given nothing or little YET he COULD "see" Allah[swt] Mercy and Justice!
can you see the difference?
additionally, did the man truly repent? we are not told, but he could have!
