I get that people don't like others to police their business. We're all grown-ups here and many of us are mavericks who prefer to do things ourselves, which is why we got into self publishing.
This is a brave new world of publishing we're in. There's a lot that's different from the way things were done before. There's a steep learning curve to conceiving of, writing, editing, publishing, promoting and selling books in this new world. One of the biggest is how to get and keep our books visible because in the indie author world, after having a great product, visibility is everything.
You need a great product. You need it to be visible to the customers who want to read it.
A great product means something that customers want to buy and read. Visibility means that it appears in front of said customers so they can buy and read it.
Because there's so much competition, people feel discouraged. How does little old me get my book in front of potential customers?
Having a great cover, a great hooky blurb, great keywords, title, tagline, preview that hooks the reader, a hooky premise -- that's how you get your book -- at base -- in front of customers. Amazon has created an environment where those attributes are rewarded. The algorithms give your book the chance that every other book gets and whether it sinks or swims is up to the quality of the product and how in demand it is to customers.
You take care of those 7 things plus writing a book that delivers on the premise and you will get that chance. If you're in KU, you get extra visibility because it's a reward for being exclusive.
Now, it's almost a given that you will do some paid promotion to get your book visibility -- on Amazon, Bookbub if you can get it, and others. Facebook ads.
Boxed sets are a way to provide readers with a sample of the work of many different authors. They are a marketing tactic to introduce authors to new readers. It's like a loss leader. I have obtained new readers through my stint in boxed sets. The first one I was in also hit the USAT. I organized a couple others that didn't but that did well.
BUT the most important part of my success as an indie was writing the book that went into that boxed set. It was a bestseller on Amazon a year earlier, not because of the boxed set. It was the #2 indie book for that qualifying week six months before I went into the boxed set. So that first boxed set I was in that hit the USAT was simply more visibility. It wasn't what made my book visible or me as an author visible. That USAT designation did not make my career. I got Bookbubs before I got the USAT. The USAT gave me other things that were valuable -- like a relationship with top indies in my genre who were NYTs and USAT bestsellers on their own merits. It taught me about organizing a boxed set and what went into it.
Those are valuable things. But they did not make me a success.
Now, I totally respect Wayne Stinnet. You can't go wrong listening to his advice or reading his books. He's proven himself in this biz. However, he is a Marine.

They're the toughest SOBs around and they can do things the hard way (they would say the right way) because a lot of what they do is the hardest stuff around.
BUT I disagree with him that it's not okay to enter a boxed set just to hit a list. That's okay. I can disagree with people I respect and still respect them.
The WHY doesn't matter to me as much as the HOW.
If you think it's going to help you get a Bookbub promo to get letters, fine. It likely will, but great reviews and great rank and a great genre appropriate cover will do that better. If you want to work with other authors and learn how to do promotions, fine. You can do that without entering a boxed set, paying thousands of dollars and using shady tactics that bend TOS or break TOS to do so.
What matters is HOW you do things. Are you bending rules and TOS? Are you finding loopholes that break the spirit of the law if not the letter? Are you breaking TOS or abusing them? Are you buying your way onto the list plain and simple? Is what you're doing scammy? Are you doing things that you don't want others to know? Is your leader enforcing secrecy rules? Are they using black hat tactics to get rank and sales? Are you participating in a blackballing of someone at the behest of your Beloved Leader?
How you treat people matters. How you behave personally matters.
We're a community. We have every right to discuss the ethics of people in our community, especially those who have clouds of smoke around them and are constantly involved in dramas about their behaviour because their reputations affect us all.