From any service, someone's presence at a political rally, followed by being present inside of the capitol building as a violent mob storms through while repres

From any service, someone's presence at a political rally, followed by being present inside of the capitol building as a violent mob storms through while representatives are evacuated in fear of their lives, is a pretty good filter, regardless of them being Parler users, for "users who are probably either insurrectionists or journalists". You can filter down from there, but even if you mistakenly think that fifty percent of Parler users just liked the idea of free speech platforms enough that they used a site frequented by the neo-nazis despite all that, it's likely that only the violent insurrectionists happened to be the ones in the crowd, and then in the capitol building, posting things to Parler as they went.