So many hear the gospel of Christ and become believers but then have no fellowship, no local church to be taught the word and no grace and knowledge to grow in. They may read their Bibles and pray but eventually they go right back doing what they were doing having no power or love and begin to question their salvation because they are not being renewed in the spirit of their mind (Eph 4:23). The Holy Spirit becomes grieved in their life, not because of sin but because they are not being feed and nourished up in the words of faith and good doctrine (1Tim 4:6). We all need to be continually built up in the faith daily just like they did in the book of Acts (they were in one accord and continued in the apostles doctrine and in fellowship, breaking bread daily).
There are others that had an emotional experience when they first believed and they are looking for that again because they associate their salvation through Christ with that experience. Then there are others that have listened to many different preachers, read many books on spirituality and have visited many churches and never seem to fit in or become settled in the faith to be rooted and grounded. They love God but they don't see any fruit and get caught up with the cares of this life. Others are dealing with their background religions that they were exposed to early in life and developed understanding that is contrary to what the scripture teach, so they are dealing with that and become confused. This is why it is so important that a believer put them self under a pastor/teacher that God has raised up and given to the church that labors extensively in the word and doctrine.
All these types of believers, and many more, gather themselves together at these crusades to get answers, to be uplifted or receive a word from God that will put them in the right direction. And the preacher has a couple of opportunities to give messages that will meet all of these needs. What takes place is that so many come forward to be saved and others to rededicate their lives hoping that something will happen to stir them up in the right direction. The Billy Graham Crusades understood that very well and was organized to get believers into good local churches. The altar call is what it is and God honored it and many became believers and many came under conviction and renewed and rekindled their love for God by receiving the love of God at those crusades.
To be very honest with you, in all the messages that I have heard come from these gatherings for the past 50 years, never once have I not heard conviction come from the pulpit. The gathering and assembly of believers is the house of God, because Jesus Christ was in the midst of His people and the word and cross of Christ was preached and many were saved and added to the church by the Lord of the harvest that compelled them to come in, that His house might be full.
And yet this was prophesied as to occur before His appearing... that it would be so bad that only a few will find the faith.
Matthew 7:
13Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14Because strait is the gate, and narrow is the way, which leadeth unto life, and
few there be that find it.
Luke 13:
24Strive to enter in at the strait gate: for many, I say unto you, will seek to enter in, and shall not be able.
25When once the master of the house is risen up, and hath shut to the door, and ye begin to stand without, and to knock at the door, saying, Lord, Lord, open unto us; and he shall answer and say unto you, I know you not whence ye are:
26Then shall ye begin to say, We have eaten and drunk in thy presence, and thou hast taught in our streets.
27But he shall say, I tell you, I know you not whence ye are; depart from me, all ye workers of iniquity.
28There shall be weeping and gnashing of teeth, when ye shall see Abraham, and Isaac, and Jacob, and all the prophets, in the kingdom of God, and you yourselves thrust out.
29And they shall come from the east, and from the west, and from the north, and from the south, and shall sit down in the kingdom of God.
30And, behold, there are last which shall be first, and there are first which shall be last.
So what is wrong with this picture if God's House is being supposedly filled by Billy Graham's Crusade?
I read Billy Graham by the testimonies from his interviews at those links in the OP as having doubts about entering into the Kingdom of God because by that commitment to follow Christ is the knowledge of sin. It is no wonder to me why he has doubts about entering in, so discern the altar call again, bro. Even if the links are circumspect with prejudices, do consider the cause as I see it due to the altar call.
Matthew 23:
12And whosoever shall exalt himself shall be abased; and he that shall humble himself shall be exalted.
13But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves, neither suffer ye them that are entering to go in.
1 Corinthians 1:
17For Christ sent me not to baptize, but to preach the gospel: not with wisdom of words,
lest the cross of Christ should be made of none effect. 18For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.19For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent.
20Where is the wise? where is the scribe? where is the disputer of this world? hath not God made foolish the wisdom of this world?
21For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe. 22For the Jews require a sign, and the Greeks seek after wisdom:
23But we preach Christ crucified, unto the Jews a stumblingblock, and unto the Greeks foolishness;
24But unto them which are called, both Jews and Greeks, Christ the power of God, and the wisdom of God.
25Because the foolishness of God is wiser than men; and the weakness of God is stronger than men.
26For ye see your calling, brethren, how that not many wise men after the flesh, not many mighty, not many noble, are called: 27But God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things which are mighty;
28And base things of the world, and things which are despised, hath God chosen, yea, and things which are not, to bring to nought things that are:
29That no flesh should glory in his presence. 30But of him are ye in Christ Jesus, who of God is made unto us wisdom, and righteousness, and sanctification, and redemption: 31That, according as it is written, He that glorieth, let him glory in the Lord.