Yes, Christina, you understand correctly.
The Lord plainly tells us that “popular Christian leaders” aren't of Him:
“Woe to you when all men shall speak well of you! For so their fathers did to the false prophets” (Luke 6:26 MKJV).
C.S. Lewis was a card-carrying member of the Anglican Church, a layman of the Church of England. No man of God serves the Whore of Babylon.
“Do you not know that your bodies are the members of Christ? Shall I then take the members of Christ and make them the members of a harlot? Let it not be” (1 Corinthians 6:15 MKJV).
Notwithstanding some of the true things Lewis said and his apparent sincerity, he wasn't born of the Spirit or walking with the Lord Jesus Christ “without the camp” (Hebrews 13:13).
Read these writings, which may give you an idea of the manner and teachings of true servants of the Lord by contrast with the false:The True Marks of a CultDiabolical Doctrines
As for being proud - how can we be proud of ourselves for what God has done with us? A man of God is one made by God, not by the man himself.
“For Who makes you to differ from another? And what do you have that you did not receive? And if you did receive it, why do you boast as if you had not received it?” (1 Corinthians 4:7 MKJV)
We take no credit for what God has done with us, and we condemn no person for not having what we do in Christ. Here is where the condemnation comes in:
John 9:39-41 MKJV
(39) And Jesus said, I have come into this world for judgment, that they who do not see might see, and that they who see might be made blind.
(40) And those of the Pharisees who were with Him heard these words, and said to Him, Are we also blind?
(41) Jesus said to them, If you were blind, you would have no sin. But now you say, We see. Therefore your sin remains.
These things are hard to believe, Christina, even impossible. Don't you realize that the religious of his day could have asked Noah the same questions you ask of us?
“But as the days of Noah were, so shall be the coming of the Son of Man” (Matthew 24:37 MKJV).