That's a good question. First, I believe that intelligence agencies are already well aware of the potential of technology like this, and at least some, like the NSA, could very well be ahead of public research. Second, research such as ours is intended to demonstrate a proof of concept, and it takes a lot of work to turn it into a reliable tool — for example, we restrict ourselves to English text. For those two reasons, I think our work does little to directly help governments and other oppressive entities. On the other hand, publicly available research is effective (we hope) in raising awareness of the threat, so on balance it does more good than harm to people writing political blogs.

As for practical tips to defeat stylometry and such, organizations like the EFF specialize in doing that, so I will leave that to them. Comparative advantage, etc. If you would like to help, you are more than welcome.