Sounds like their forum had a hands-off moderation policy (which most do, given the amount of work it takes to run a forum like we do).
As much as I hate to do so, we have on a number of occasions needed to delete posts and indeed entire threads by people who, in our judgement, stepped over the line as to what is acceptable. There has also indeed been the occasion of "cease and desist" letters from lawyers representing third parties who were upset by some of the remarks made here.
My personal approach is one of humility in these things. It does not pay to be so proud of the posts or any supposed "right of freedom of speech", that you cannot see the sane alternative of just removing the contentious posts and moving on with your life. Crusading is all well and good, but doing it using a vehicle which could hurt many more people than those actually making the statements is neither appropriate, nor wise, in my opinion. There are other such vehicles which may be more suitable. Publish your own website or blog if it is that important for you to get your message out there.