I don't think "freedom of expression" is ever absolute, anywhere, nor do I think Theymos thinks it should be on bitcointalk (as evidenced by some of the rules, the presence of moderators, and even his banning of the last Yobit campaign). If there was absolute freedom, then spamming would be allowed--and it's not, and I think common sense would dictate that there are limits to how shitty posts/threads can be before they get deleted. Otherwise it's just a set up for the implosion of this forum, a scenario where there's nothing but AI-written crap and sig shitposters driving away all of the good members.
When was the last time you reported a post that you considered spam? Moderators on the forum act almost exclusively on the basis of reports, if there are none or there are relatively few of them, then it is clear that the majority of spam is not sanctioned, which means that it passes under the radar.
In other words, all the rules of this world are in vain if there are not those who point out their violation, and then those who impose punishments based on that.
And I wonder why a lot of those good members of old did go away. Some of them we know the reasons for, but I have a feeling some left because the level of discussion quality here has deteriorated and it's become tedious to see the same thread topics come up over and over again. I'd really, really like to know Theymos's thoughts on this, but I don't suspect he'll give his opinion anytime soon.
There are probably those members who have left the forum because they are dissatisfied with how things work, and the diminishing quality of posts and discussions certainly plays a role in that. If you start putting board after board on ignore and if you see that nothing changes for the better, then it is not strange that one day someone decides that there is nothing here for him anymore.
Although I would dare to say that the disappearance of sig campaigns that paid more than twice as much as the case today influenced some to leave the forum.