There are several different versions of Windows including those for Home and Pro users, upgrades to Enterprise and Education editions, a mobile version that runs on ARM-based phones, an IoT version that runs on a Raspberry Pi, and server versions.

If you cover the whole market from thumbdrives to server farms, you're obviously going to make different versions to fit different usage scenarios. People do that with Linux, too.

Windows 10S is just a new version of Windows 10 Pro that addresses certain needs in the education market in particular.

If you don't want it, don't buy it. If you buy it and decide you don't like it, you can upgrade it to Windows 10 Pro. No big deal.

It's frankly insane to have hissy fits about it destroying civilization as we know it. It's not.