They decided to ruin it because that's what their company motto is, they enjoy Just Annoying Greatly Enduced Xenophobes.
Yes, JaGeX are the creators of RuneScape. Paul and Andrew Gower formed JaGeX.
Jagex has been in control of RuneScape ever since its launch in 2001, because RuneScape creator Andrew Gower was the founder of Jagex.
No, Jagex is in England.
runescape was made by jagex by the brothers paul gower and Andrew gower who later formed jagex in the jagex studios at cambridge,England
Jagex
'Hacking' RuneScape in any way is violation of Jagex's Terms and Conditions. This is because hacking RuneScape or other systems of Jagex is an infringement of Jagex's intellectual property rights, which is against the law.
Runescape was made by Jagex.
Jagex LTD
They do because the NPCs -yellow dots and some other players are Jagex staff that enforce the rules of Runescape.
You can email Jagex, but if you have ideas discuss them on the forums.
Jagex is currently dedicating a lot of efforts to do something about bots and gold farmers, who also ruin the game. I suspect they are overwhelmed by the sheer amount of cases in which there are problems.
There is no editor for Runescape. The only people that have the programs to edit or change Runescape is Jagex.