I made a statement that the relationship is informal and back up my claim. If you get offended by me simply saying things that are true, that's not a good basis to have a conversation about philosophic matters.
If David Deutsch would have decided to hire you as an editor, that's would be a clear sign that he values your expertise enough to pay for it. The information that you provided shows that you provided a valuable service to him by organising an online forum as a volunteer and as a result he saw you as a friend who got to read his draft and he listened to your feedback on his draft. You seem to think that the fact that you spent the most time on providing feedback makes you the most important editor of it, but there's no statement of David Deutsch himself in the acknowledgement section that suggests that he thinks the same way.
There literally is such a statement as the one you deny exists: he put the word "especially" before my name. He also told me directly. You are being dishonest and biased.
Your comments about organizing a forum, etc, are also factually false. You don't know what you're talking about and should stop making false claims.