Let's stand up for the truth regardless of threats from Geoff/Leverage, and let's stand up for the truth regardless of the mob. 

I feel like it's going to be really hard to say anything without people pigeonholing me into belonging to some group that is trying to rewrite the rationality social and political landscape some way.

Let's stand up for the truth! Maintaining some aura of neutrality or impartiality at the expense of the truth would be IMO quite obviously bad. 

I myself have access to some sensitive and somewhat confidential information, and am struggling with navigating exactly which parts are OK to share and which ones are not.

I think that it is seen as not very normative on LW to say "I know things, confidential things I will not share, and because of that I have a very [bad/good] impression of this person or group". But IMO its important to surface. Vouching is an important social process.