when the TF2 mods that were barred on these grounds are currently in the process of being released on steam.
TF2 now has an official SDK which those mods are using instead of the source code leaks. There is no equivalent SDK for CS:GO/CS2.
The fact that every other sourcemod that isn't based on leaked code has always been approved suggests that there's something else at play here.
I hope they're able to resolve whatever the issue is. In theory there's nothing stopping them from just releasing it as a standalone sourcemod, like those TF2 projects before the official SDK was out, unless they've attached their real identities to the mod. If not, there's always the newly announced CS:Legacy (which uses Source SDK 2013) I guess.