Bringing more widespread awareness to niche issues most people aren't aware of is, by some infinitesimally small percentage perhaps, more likely to have an impact on bureacracy than trying to act alone. Or maybe they know things aren't going to change, and are complaining on their personal blog to have a vent, which they are perfectly well within their rights to do. Just like you're allowed to complain about their complaining blog post, and I'm allowed to complain about your complaining comments about their complaining blog post. I think your complaining comments about their complaining blog post are rather more annoying and less interesting to read than their complaining blog post, but I suppose you'll probably think my complaining comment about your complaining comments about their annoying blog post are more annoying still :)

Terence Eden's blog is very influential in the world of the UK technology civil service.

Writing about it there is a lot more likely to have a positive result than writing to his MP.

The author is a former civil servant. I think it's safe to assume he knows that writing to his MP is an option...