Blizzard is a company and basically all they care about is money. So they need subscribers. Its kind of hard to find new players for such an old game. And its hard for new to get into such a old game. So Blizzard has to care about their old players. ofc they don`t like bots. So Blizzard has to at least pretend to do something against bots. The best way to show the community that they are doing something is to go to court. Blizzard knows, that eaven if they shut down hb, it will only take a few weeks untill a new bot comes up.
And there`s that other thing.... If they ban all bots in the game, how many players would be left? 3/4? And if they ban an obvious bot account wich is obviously trying to make gold an sell it. How high is the chance, that the owner of that account already made money out of it an will reinvest it into a new account and buy the game, the addons and gametime again?
In my oppinion they try to keep it in balance. They want to satisfy the real players by pretending to do something against botters and they don`t push to hard against botters so that the botters will keep on botting eaven if one account gets locked down.
If they wanted to do something against bots, they should employ some guy from the street that has never seen a videogame and give him a crashcourse in bot behavior, place him in a battleground and he could ban at least 5 accounts every minute. I personally wouldn`t need any fancy warden software to detect a botter.