This is a good question. For two reasons. The first is this is true at all, which I’m not sure. The second is the comparison to developers.
As a developer and manager of both kinds of teams, I remember being more open and hearing more about dev meetings in user groups, and not much on the tester side (although there were some). However, it was more QA oriented (formal, ISO, things like that, rather than new methodology to test).
Do developers tend to share more? Or is it the type of craft that’s easy to communicate? All the idioms are already in place: WCF, C#, patterns, design. And every developers know them. Is it not like that in the tester community?