I take two things from the lack of answers provided by "Chistians" at the CH.
1) They agree with the statement that certain people meet a fate that was planned for them, which is that they will stumble and fall due to unbelief. They also agree that others are chosen to be priests, to be a nation and to live in the light.
2) They don't agree with #1, but they cannot come up with anything to refute God's word so they stay silent.
3) I don't generally read the "Questions for Christians" section.
... but as long as I am here.
1 Peter 2:8 NASB and, “A STONE OF STUMBLING AND A ROCK OF OFFENSE”; for they stumble because they are disobedient to the word, and to this doom they were also appointed [G5087].
The word that is causing people grief is "appointed " or in Greek "tithēmi" [G5087].
STRONGS NT 5087: τίθημι: to make one one's own, as τινα φίλον to make one a friend, see Passow, p. 1893a; (Liddell and Scott, under the word, B. I.)). τιθέναι τινα εἰς τί, to appoint one to (destine one to be) anything, passive, 1 Peter 2:8; [Thayer's Greek Lexicon]
Note that it is a 'passive' destiny in this particular use of the word (according to the Greek grammar). Thus the section of 1 Peter 2 quoted is saying nothing more than some will believe Jesus and some will not. To those who believe, He is destined to be a treasure. To those who do not believe, Jesus is destined to be a stumbling block. Both the believer and the unbeliever have found their destiny.
It seems to me that we will need to look elsewhere for a 'smoking gun' verse that God predestines some to hell. This is not such a verse. However, I see in this chapter an assurance that there are no people who 'slip through the cracks'. Those who are destined to believe, will believe and those who are destined to reject Christ, will reject Him. No human effort will change what God has foreknown will be.
So check it out in the larger context ...
1 Peter 2:1-12 NASB
1 Therefore, putting aside all malice and all deceit and hypocrisy and envy and all slander, 2 like newborn babies, long for the pure milk of the word, so that by it you may grow in respect to salvation, 3 if you have tasted the kindness of the Lord.
4 And coming to Him as to a living stone which has been rejected by men, but is choice and precious in the sight of God, 5 you also, as living stones, [fn]are being built up as a spiritual house for a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ. 6 For this is contained in Scripture:
“BEHOLD, I LAY IN ZION A CHOICE STONE, A PRECIOUS CORNER stone,
AND HE WHO BELIEVES IN HIM WILL NOT BE DISAPPOINTED.”
7 This precious value, then, is for you who believe; but for those who disbelieve,
“THE STONE WHICH THE BUILDERS REJECTED,
THIS BECAME THE VERY CORNER stone,”
8 and,
“A STONE OF STUMBLING AND A ROCK OF OFFENSE”;
for they stumble because they are disobedient to the word, and to this doom they were also appointed.
9 But you are A CHOSEN RACE, A royal PRIESTHOOD, A HOLY NATION, A PEOPLE FOR God’s OWN POSSESSION, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light; 10 for you once were NOT A PEOPLE, but now you are THE PEOPLE OF GOD; you had NOT RECEIVED MERCY, but now you have RECEIVED MERCY.
11 Beloved, I urge you as aliens and strangers to abstain from fleshly lusts which wage war against the soul. 12 Keep your behavior excellent among the Gentiles, so that in the thing in which they slander you as evildoers, they may because of your good deeds, as they observe them, glorify God in the day of visitation.
God Bless.