It appears to me that they are going more by reason than scripture.  They are making some logical deductions without scriptural support.  That the people of God had self esteem it very clear.  The disciples were constantly debating who would be greatest among them.  Lu 22:24 And there was also a strife among them, which of them should be accounted the greatest.  Lu 22:26  But ye shall not be so: but he that is greatest among you, let him be as the younger; and he that is chief, as he that doth serve.

The Lord rebuked them for their egoistical thinking.  He even taught them that when they had done all their duty they should still consider themselves "unprofitable servant."  Lu 17:10 So likewise ye, when ye shall have done all those things which are commanded you, say, We are unprofitable servants: we have done that which was our duty to do.  The word "unprofitable means "useless"  [that is, in and of themselves]

Paul could say of himself, Phil 3:3 For we are the circumcision, which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh.  Where there is self-esteem there is confidence in the self. He says he had "no confidence in the flesh"

It the secular world we have various abilities. To have confidence in these is not wrong, however, in the things of the Lord there is no place for the things of self.

Pr 3:26  For the LORD shall be thy confidence, and shall keep thy foot from being taken.

Ga 5:10  I have confidence in you through the Lord, that ye will be none otherwise minded: but he that troubleth you shall bear his judgment, whosoever he be.

The whole concept of discipleship is a denial of the self life.   Lu 9:23  And he said to them all, If any man will come after me, let him deny himself, and take up his cross daily, and follow me.

To teach self-esteem--worth or love in the things of the Lord is wrong.   1Pet. 4:11  If any man speak, let him speak as the oracles of God; if any man minister, let him do it as of the ability which God giveth: that God in all things may be glorified through Jesus Christ, to whom be praise and dominion for ever and ever. Amen.

I have often said that a person all wrapped up in themselves make a very small package.