I think the problem here is that ReactOS wants to keep Windows compatibility. Don't forget ReactOS started out as an NT5 clone; I doubt porting Windows XP's NTLDR to UEFI would be as trivial as you may think it is.
Based on https://jira.reactos.org/browse/CORE-16175, I think the project is using Microsoft's bootloader to load the ReactOS kernel during the testing phase. If that's the level of compatibility they're going for, I can imagine implementing full UEFI support will take ages.
As soon as I read UEFI in the news letter I knew this forum post would end up in the comments :). The newsletter is about UEFI class 3, I.e. no CSM, where that is not. There are some later posts in that thread about using UefiSeven which is a project which hacks minimal int10h support but at that point you might as well just have modified freeloader for proper support instead.
The source code for the bootloader doesn't seem all that complicated: https://github.com/reactos/reactos/tree/master/boot/freeldr Basic support seems to be finished, but there are still a few open tasks regarding EFI support: https://jira.reactos.org/browse/CORE-9841?jql=labels%20%3D%2....
Based on https://jira.reactos.org/browse/CORE-16175, I think the project is using Microsoft's bootloader to load the ReactOS kernel during the testing phase. If that's the level of compatibility they're going for, I can imagine implementing full UEFI support will take ages.