Do you honestly think if Blizz actually cared about dealing with bots, farmers, spammers, and cheaters that they would be having these issues? No, they would have hired a few folks from the data security industry, a few lawyers to go quash the spammers' websites, and that would be the end of the problem.
The fact that spammers can post with impunity to the message boards, to say nothing of the fact that their websites remain untouched, just shows that Blizz doesn't care about this issue. If anything, they're somewhat dependent on the spammers and farmers as it helps drive up the prices on the all-important RMAH.
Wow, it's impressive just how clueless you are about the subject matter.
We'll start with the one that's most fun to address. Taking down websites. Explain to me, smart guy, how does Blizzard do this? Explain to us all the process of taking down someone else's website. Organizations like the MPAA and the RIAA, with far more money and influence than Blizzard could ever hope to have, can't even take down websites blatantly violating their copyrights on a daily basis, despite having been trying to do exactly this for years on end, but somehow Blizzard will just push the magical shutdown button nobody else knows about?
Now moving on to the botting problem. How do you know they do not have experts working on this? Do you really think it's this black and white? Why are there security vulnerabilities in pretty much all software that exists? Why do viruses still exist? Why are constant security updates needed for pretty much any software that interacts with the Internet in some way? Do none of them hire experts? I guess not, because if they did they'd have 100% solved all security flaws in like 3 seconds, amirite?
The fact is, the best bots will come from private websites, which sell access to their hacks/bots/etc to users. For these private websites, it's not only in their best interest to keep a skilled staff that can create these programs for popular games, but also to keep these programs as undetectable as possible. As such, it's a constant arms race between the developers of the game and the creators of the bots/hacks/etc. It's an unwinnable scenario as long as enough people are willing to pay money for these hacks/bots/etc (and they are), the best you can do is contain it.