Razer, Why is the FN key not customizable? Huntsman TE is almost perfect.

I use IJKL movement because it enables access to other keys. The 30 dollar steelseries keyboard I was using before allowed me to rebind the steelseries key itself. Yet I cannot rebind the fn key on a 130 buck keyboard? Come on, this one thing is making me consider buying the Apex Pro TKL instead and returning this. Please fix this.