I completely agree with the argument, just let them read what they want! However, if your reader struggles reading, guidance is definitely needed for a few reasons, but consider this one: there is a direct correlation between the reading skills and the desire to read. If you do not accomplish something well, do you want to continue doing it? I know I don't, so when I think of their struggle in that light, I am all on fire to help them find something that will spark their interest and increase their ability to read well.
How do you help them pick a book?
There are so many things to consider! First, personal choice is an important factor to consider if you want your unmotivated reader to want to read. You want them to pick something that will interest them, but you also don't want something that will be so difficult they will just be frustrated with reading. You also want text that will challenge them a bit, but not overwhelm them. After all that, picking a book can be a daunting task.
If they finally find a book, begin with the fist rule: read the first page, if five or more words are too difficult to understand or recognize automatically, then it's probably too hard. Put it aside. Don't discourage them from reading it, just make it a goal! I know you want to read this, so let's put it here and continue to practice reading until you can read it on your own. Or you could read it together. Avoid "NO!" just encourage, support, and motivate your reader to be able to read it in their near future with a bit more hard work. In the mean time, the most effective way to read better is to read more! So don't stop reading just because this one book is too hard. Help them pick books they can read that won't overwhelm them while they learn the tools to actively read.
Is this possible?
Thankfully in today's day and age, it is. We have access to every kind of book we can imagine. My local library, Goodreads, and Amazon are my BFF's. The key is to find books about whatever interests them. For example, I had a student who loved to trap shoot, but hated reading. So I found a book about trap shooting, we read it together, then I went trap shooting with his dad and one of his friends. It was a lot of fun! And it was at this point that a relationship of trust was built because he realized that I cared about what he enjoyed. After this he began to implement some of the strategies I had been attempting to teach him previously without success.
You want your reader to interact with the text before, during, and after reading. You want them to think about what they already know about the topic, you want them to predict, connect, ask questions, visualize, identify text features, use context clues to understand vocabulary, etc. etc. If reading to understand is your goal, and you want your reader to pick any old book and read it successfully on their own then giving them the cognitive skills to understand their reading is your primary goal. That way they can pick any old book and read it effectively even when/if they struggle at times.
If they insist upon reading a book that is clearly too difficult for them, don't discourage them, but I do encourage you to try two different approaches that have worked for me:
Read it together. Sometimes they did not go for this, especially at the secondary level, so then I'd go with number 2...
Set it aside as a motivator. My conversations would go something like this: "Okay, so you want to read this book and I'm all about you reading this book. However, in order to read this book you must read these five books first." The goal is to get them reading, reading, reading because it is the only "strategy" that will make them a better reader! (Go figure, right?) So strategically place books that you know your reader will be successful with, increasing the difficulty, within their interest, giving them the tools to self-monitor, so that by the time they get to that desired book, they are more likely to be able to read it well.
In the end, our job as educators is to provide high quality literature for our students. It seems a daunting task when you look at all that is available and a students reading ability. What I find, however, is that too often I'm too worried about their ability and not as focused on what the student wants to read. The fact that a student wants to read is super exciting! So find that book because any old book won't do!