Just to be clear: Kay Yu isn't trying to kill modding, this is all just a result of an otherwise beneficial change.
HoloCure, which is made in GameMaker, is moving from targeting the GameMaker virtual machine (VM) to the YoYo Compiler (YYC). This is a big deal.
HoloCure currently uses the VM target, which includes compiled bytecode[^1].
In the upcoming 0.6 update, Kay Yu has made the decision to switch to targeting YYC, which compiles GML to machine code (through means not important in this discussion).