In fact, all three revolve around specifically theological content.
Also, you "forgot" to post the information I requested. I'll ask again:
"By the way, where does the Bible state that Christians should not read theology or engage in theological discussion?"
1. Theological books are not like preaching or discussion. Preaching by a good preacher is hearing a man of God expound on the word of God and judging his words by scripture. Discussion is exchange of ideas as guided by scripture. Theological books are some guy, typically claiming to be a Ph.D. or something pretentious, writing down their ideas as if they are gospel in a book to make it look like it's true because it's in black and white.
2. "And further, by these, my son, be admonished: of making many books there is no end; and much study is a weariness of the flesh." Ecclesiastes 12:12
3. Theological books are totally unnecessary.
"But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him" 1 John 2:17
Instead of spending time reading books by some guy claiming he has the truth because he went to some school or seminary, read the Bible. No books, no commentaries, no study Bibles. Read the Bible. There are a lot of people that read theology books who haven't even read every book in the Bible. I have never heard of any theology book that will teach me anything more than the Bible will. The main difference between theological books and the Bible is that the Bible is the word of God, and other books are the words of men.