On the contrary, Gary Thomas is a Christian writer-in-residence at Second Baptist Church in Houston, Tx., an adjunct faculty member at Western Seminary and Houston Theological Seminary and the author of more than twenty books based on Biblical teachings. He is also a speaker in 49 states and 10 countries as well as a regular guest on national radio and television programs like CBN, Focus on the Family and Family Life Today.
None of that actually demonstrates that this particular book is theologically and doctrinally based. Perhaps you do not know what I mean by that. I will clarify. To be theologically based it would need the use of theology as support for its claims in accordance with Christian theology (who God is and in relation to us). To be doctrinally based it would need to be a direct result of the doctrines of Christianity. If not, it is based on behaviors and dealing with behaviors of others. Which may be Christian and also may borrow from the secular world. The word "toxic"itself is borrowed from the mental health field.
In any case, I can only go on the quotes you have given, and that is what I am basing my perception on.
The entire book is backed by Biblical teaching and there are numerous Biblical references therein.
So is most of the Quran and the Book of Mormon. They just interpret the Bible differently. Teaching is one thing. Theology is another. Doctrine yet another.
Do you have any evidence of the above bolded part of your quote?
1 Thes 2:10-12 You are witnesses,and God also , how holy and righteous and blameless was our conduct toward you believers. For you know how, like a father with his children, we exhorted each one of you and encouraged you and charged you to walk in a manner worthy of God, who calls you into his own kingdom and glory.
Col 4:5-6 Be wise in the way you act toward outsiders; make the most of every opportnity, Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.
Romans 12:2 Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is--his good, pleasing and perfect will. 3. For by the grace given me I say to every one of you: Do not think of yourself more highly than you ought, but rather think of yourself with sober judgement, in accordance with the faith God has distributed to each of you.
Eph 4:22-24 You were taught, with regard to your former way of life, to put off your old self, which is being corrupted by its deceitful desires; to be made new in the attitude of your minds; and to put on the new self, created to be like God in true righteousness and holiness. 26-27In your anger do not sin: Do not let the sun go down while you are still angry, and do not give the devil a foothold.
Luke 6:28 bless those who curse you, pray for those who mistreat you.
A lot of the problems we have with others that we may see as toxic, begin in ourselves, or are exasperated by things in ourselves. When we deal with those in prayer and supplication we will find ourselves less affected by the behaviors of others. That is why I see difficult situations as opportunities for sanctification in areas of us, that we didn't even know needed sanctifying as per He who began a good work in you will complete it. If we always run and hide from unpleasantness, those hidden sins will not be exposed. It is good to pray as David did, for God to reveal to us any hidden sins that we might walk in the ways of righteousness.