[TopQuark]

They are so confident that they are loved children of God that they know their worth,

You are confused: self-esteem is the attitude of a person towards seld; G-d's love comes from without.

This statement also implies that an atheist cannot have high self-esteem, which is patently false.

[sinkspur]

You are confused: self-esteem is the attitude of a person towards seld; G-d's love comes from without.

Not confused at all. Awareness of God's love is a strong contributor to self-esteem.

As for atheists, of course they can have high self-esteem. I just don't know how they do so without God.