it's not about ethics. you're making this a bigger deal than it actually is.
See, people have this misconception issue where they feel that the things that exist in their world have to be tailored exactly to them and that the wants and needs of the majority of consumers do not apply to them. They also feel that when these needs aren't met that it is personal.
Here's the thing: iOS updates aren't strictly feature upgrades. They are enhancements to the way the OS operates, and are also heavily geared toward security. In the mobile world, threats can appear very quickly. Using an outdated operating system only makes you more at risk for these types of problems.
If you COULD go back to 6, you'd be temporarily happy. You'd have some improvements to speed and what not, but you'd be without most apps (which are also updated to fix bugs and security flaws) and all the new iOS features. Not to mention, you'll have to get a new phone at some point in the future.
This is not an "ethical" problem in the slightest. Again, this is you taking things personal. Apple is not letting everyone else downgrade except you. They are focusing their energies on new technologies and features. They certainly are not focusing their energies on allowing people to downgrade to a 2 year old OS. They'd much rather focus on the people who want to upgrade.
20% of Android users are on 4.0 or earlier. 4.0 was released in 2011. Many of these users would update if they could.