The RPI-TFT image is for the RPi 1 and does not have a kernel that works with the RPi 3.

For the RPi3, you will need to start with the RPi3 image, and follow the instructions for your particular TFT screen to set it up.

Although looking at the GitHub that they provide in the Kuman documentation... I would read through it closely instead of just running their script.

https://github.com/goodtft/LCD-show is the GitHub they link to, and has the files needed, although some of them shouldn't be needed to be installed as kali-rolling has the same, or newer versions of the required packages.

The main things you need are the config files that are copied into /etc/X11/xorg.conf/d and the config.txt file, and possible the .dtb file (which they put into /boot/dts/overlays and rename to whatever.dtbo.

The steps to do this aren't really something we cover in the bug tracker as it covers bugs not technical support. If you would like assistance with that, I would suggest asking in our IRC channel or on our forums.