Yeah, what I meant was "How is that an attack on 'the bitcoin net'"? It's not.
In theory, if a single botnet/coalition of botnets gained over 50% of the network, they could start double spending.
Otherwise, they are just hardening the block chain.
We know botnets can get really big if they're run by clever people. The question I have is, if someone creates a clever botnet and turns it on once mining has become unattractive financially to those who pay their own electric bills, isn't getting over 50% pretty feasible?