Not sure if this is truly a Kile problem or a problem introduced by Ubuntu, but it is annoying that installation of Kile on Ubuntu Mate tries to force a full LaTeX installation when I only want a plain TeX system. This means I have to create a dummy LaTeX install first, then install a plain TeX system by hand.
Yep, there is nothing we can do about the Ubuntu package for Kile. You have to report this issue in the Ubuntu bug tracker: https://bugs.launchpad.net/ubuntu/