I, in all honesty, don't understand why it isnt allowed. If i could get some kind of understandable reason i'd be satisfied and leave it be, but i really like Better HUD since it does what WAILA and derivation of it like WAWLA and much more, like showing FpS without F3 and show armor and tool stats without separate mods. it also shows what cardinal direction you are facing in a much more precise manner than a minimap, heck it even shows light level and HP/HB in numbers (also saturation) it's is simply too usefull to leave out imo.
That mod isn't on our whitelist for client side mods. To request to be added please post the screenshot of the error that gives you when you try join the server, and the server you play. For reference here is the mod page on MinecraftForum.net
