The author of Bitcoin XT has previously stated that he would force the fork to occur without consensus. This is problematic because without consensus we would have two blockchains, and because that author has decided to take (near) dictatorial power over Bitcoin. Two blockchains can cause a loss of confidence and thus a drop in brice. There are also a whole host of other issues since they would be operating on the same network.
So it is also related to block size debates
It sounds like a an endless contravention matter, and it is difficult to gather the community upon one view.
Thanks for your explanation