In my opinion, the locked thread was becoming UNcivil. It went beyond "chatter", moving into an uglier state, where people's attitudes on the topic could make enemies out of what should be friends here.
On the other board, the censorship involved topics related to hiking -- rescues, fatalities, lightning -- all related to Mt Whitney. We try hard not to censor those. But it could happen there, too, if things become uncivil.
In the locked thread, pretty much everyone who wanted had plenty of time to state their case. It got to the point that people were just rehashing their opinions. The discussion was making the moderators edgy. Some here have a higher threshold of what is civil, but I am sure there are others who would read and never come back because what was written already was beyond reasonable.
I know locking (or worse, deleting) a thread rubs some people the wrong way, but I am pretty sure it is ok with others. There is no way everyone is going to be happy with our actions. I am sorry for that.