FMS has a feature where anyone can publish a CAPTCHA, and solving this will add you to that person's trust list automatically (with a low score), but this is pretty vulnerable to DoS attacks. Paying some bitcoins is also a good idea.
I would say this is possibly even more limiting on free speech than just using a centralized forum. The idea that a newbie would have to pay to get their posts seen isn't too great imo. I know that if that were the case I wouldn't have joined (as I would not have the funds to be able to pay comfortably), and I'm sure several others wouldn't have either.