I think you have to realize that this site and others like it, are privately owned domaines, while their titles suggest they are "for the public". The owners and admins have their own set of opinions and beliefs that sometimes steer these discussions and topics.
So while at times you will see freedom of speech vehemently defended here on some topics you will see some editing in other areas by the moderators in others.
Its their website and they will do with it what they please.
This issue of private ownership of public websites in terms of steering agendas has reached the highest levels of government.