Maybe the miners should stick to mining, is my point.
Sure, but your missing the fact the miners have right to choose what client and what changes to activate. They can merge the code they like or use any clone of Bitcoin repository or whatever. Most devs are miners as well, or at least were at one point in time. Bitcoin and all voting is based on proof of work, not on github/bitcoin - but miners are free to use and run code from this place if they choose to, but it is not required.
It's simply how Bitcoin works at the protocol level, succinctly described by satoshi in the white paper. The protocol, by itself, doesn't decide right or wrong, its participants do, and they vote with their CPU's (or influence those that do by buying or selling on the market.)
Nice to see someone understand how Bitcoin works.