I can understand the modded community is frustrated at Mojang about the relatively poor updates which are really only interesting to PURE VANNILA players that haven't played with stuff that is already avaiable in mods, but this was a great change for the modded community. If one just thinks it's from a mod, even the good things Mojang does for the modded community are ignored.
I can't speak for the community, but I personally am not in the least frustrated with Mojang. I honestly think they're doing a good job, and have done so for the nearly four years I've owned a copy of Minecraft.
That said, I had seen claims made both ways (vanilla change versus Forge change) at the time I wrote my initial response to this thread, and I really, honestly, truly, cannot be bothered to hunt down the facts. Ultimately, even in my guise as occasional dabbler in mod writing, it doesn't really matter -- I am grateful to whomever made it happen, and made it work well, without needing to be specific about it*.
I'd like to ask you not to read into my words things that I've not said; I am not a modded community, I am not frustrated with anyone, and I don't 'just think' anything is from a mod or otherwise.
* In fact, I'm willing to bet it's more than just a vanilla change: I have no doubt the Forge team needed to make careful changes to their API to support this, as well as carefully testing that as few things as possible broke in the various edge cases I can't currently imagine, but which I am certain exist.