When you use Scripture, are you throwing Scriptures too, or is that just other people?
Secondly, you're correct, it is all about your theory, not Biblical exegesis and proper context.
You are aware, are you not, that Joshua 24:15 is not a Gospel invitation to salvation, right? Listen on and learn, please.
Or, do you just dismiss context outright, and conveniently misinterpret it via tradition and ignorance?
Furthermore, you are aware, are you not, that no man chooses their way to heaven? John 1:13, Romans 9:16, James 1:18, 1 Peter 1:1-3, John 6:63, and, that no man is able to come to God, John 6:44? These Scriptures show your error (yes, you're in error, accept it) in mishandling Joshua 24:15, taking it out of context and getting false doctrine. My hope is that this will humble you, that you will finally receive correction and grow in knowledge and truth.