Suggest: a way to kill X class

I think there should be a project made such that we are allowed to kill x class planets, its very frustrating when you explore a x class planet and because its a lowland gas planet you do not wish to cluster it and you had to purposefully leave Dp without a fleet so that someone hits u for free just to get rid of that planet. what about X U planets, arent those just dead objects running around? i wonder how many of them there are already here