Why?
WoW is removing it's open world PvP servers.
CCP had to step in to restrict PvP'ers.
Lots of other games have a variation of this same mode system, so PvP is by consent only.
PvP is not a fix all for any game.
And it only encourages people to get nasty on the games forums when they join a game that isn't PvP based, just like Elite.
I've seen this behaviour in Star Trek Online, in Warframe and even with WoW and EVE. Even UO had to step in to control PvP.
PvP'ers get nasty and demand everyone else have to play their way. It's a vile attitude to bring into a game.
So PvP in mixed mode games don't grow the game, it divides it. Just like we see here.
And this game wasn't built with PvP Objective game play in mind.
It's a PvE token pushing game. You attack and defend the same way.
And the only thing you are "making sure" of, is that we don't get bored on the forums