If anyone wishes to make a contentious post about any individual or organisation, we insist that they identify themselves to the Pprune staff so that any subsequent action can be directed to the correct individual. If we feel that a thread is getting close to being actionable (or just rude and unacceptable), we will pull it and warn the offenders about their behaviour. We may also withold their posting rights or, in extremis, ban them from Pprune.
Remember, free speech carries responsibilities and liabilities. We won't let Pprune be put at risk by intemperate idiots.