If you create a cryptocurrency, and you own all the coins, that coin is worthless. The coin doesn't have value unless people are using it, and because you own all the coins, no one is using it.

I don't see how this relates to anything that has been said so far.

Pre-Mine

Pre-mined, acquired before mining. It's an investor thing. If you have the budget to do so, you can seize this opportunity along with anyone else who meets the wealth requirement.

Ninja-mine

This is crap. It's coins that aren't even supposed to exist, usually given to someone in a very illegitimate way. Simply put, it's abuse. They cause nothing but devaluation. The fact they exist or have existed at some point spells out developer bullshit.