In reading many of these posts, it's apparent many don't understand what the word ethics even means. Assume that gifting 1000 copies is in fact allowable under the TOS. It's spelled out in black and white, "You may gift 1000 copies of your book." Doing so isn't unethical. Unethical behavior is intentionally breaking a rule, be that sexual harassment in the workplace, or fart jokes at church. If there's a rule against it and you knowingly ignore the rule, you are unethical. An ethical person knows it isn't right to make an off-color remark to a female coworker about the tightness of her jeans. A moral person wouldn't.
The question then becomes, is buying your way onto one of the BS lists morally acceptable.
My last release, in a new and smaller series debuted at #118 on Amazon. The one before that, in a longer, more popular series, debuted at #96. Before that #183, then the 300s, and 700s, and so on. An email to my subscribers and a Facebook post, plus the new release email from BookBub and Amazon are the only things I use in all my launches. No paid advertising. Only those people who want to pay me for my work get to see it. Period. One day, I will be a New York Times Best Seller. Because people will buy and read my books. Am I jealous of those who took a short-cut? KindleSpy me and find your answer.
In any endeavor there are shortcuts. I once worked in construction and saw first-hand how shortcuts don't work. A ten story condo I was working in pancaked, killing five men and a sixth lost a leg, not diving through a doorway fast enough. There is a right and wrong way to do anything. The right way, and by that, I mean what will give a person like me the most personal satisfaction, the most pride in accomplishment, is to put their shoulder against the wheel and push with everything they have. Even if you come up short, you can hold your head high and say, "I did the best I could."
It is possible to become a top selling author and be an indie. A lot have done so and continue to do so. Starting a marathon, and jumping on the back of the camera motorcycle until it gets a hundred yards from the finish line, then jumping off and running across to garner your accolades can't feel very good. But, that's just the opinion of one man with a very narrow moral compass.