Against Herobrine:
I have a possible explanation on why "Removed Herobrine" appears so many times in the Minecraft update logs.
I heard that after Herobrine stories became mainstream within the Minecraft community, Mojang posted that on the update logs because of all the ridiculous stories making Minecraft look dumb. It does stand to reason, I know someone who didn't get Minecraft because of a bunch of Herobrine junk.
Yes, I did read the post and the information about the Human Mob stuff. Just thought I would throw this out there.