blizzard care about botters, atm people think they can get away with the constant bg botting so they do it.
imagine back in cata, there might have been 10 or so bots in an AV game... the bots are coded to do things like "move to biggest fight" or "Assault base XX" etc, and when the biggest fight comprises of actual humans then the bots are actually pretty undetectable. Nowadays (with MoP being so new) things like rep farming, gold, gathering mats etc are in strong demand, not to mention farming honor for gear upgrades etc. This makes botting more desirable. I personally never thought I would start botting but I wanted to level some chars (and hate the levelling process) and a friend said he'd been doing it for a while. The first time I saw a level 10 hunter traverse a spiral staircase I was hooked.
I think it's like that for a lot of people, they hear how good it is from other people, they see that their friends haven't been banned in a year of use and this spurs them on to buy the bots themselves - this then spirals out of control.
Until BGbuddy has better, more randomized pathing (or the Ultimate PVP Suite botbase is released) it's just too easy/risky to get caught or reported in a battleground due to them amount of other buddies around.