Why assume they are his children ? Why not just look at the fruit as the LORD Jesus Christ commanded ? Do not judge them. Judge their fruit. The judgment belongs to Messiah.
Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them. Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
Hebrews 12:6 -
For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
Proverbs 3:12 - For whom the LORD loves he corrects; even as a father the son in whom he delights.
And, I do think they started out with good intentions and did bear good fruit. You are free to believe what you want, and I’ll do the same.