Hello Berliegh.
I hope that the weather where you are is better than it is here

The locking of topics is usually a last resort. Should staff feel that a certain topic has lost its direction, or that contributors have be come belligerent to the point where it becomes detrimental to its members and the site then a topic will be locked. Often a topic is locked to allow for a cooling off period and then unlocked. Before a topic is locked staff will generally warn the participants that their conduct is unacceptable before going forward to lock the topic.
It is unfortunate that this has to happen as its the good topics that suffer along with those who make worthwhile contributions.
New topics can be restarted where locked topics left off and usually these topics can flourish as members can see why the old topic was lock and act accordingly. That being said, should the new topic degrade into a shouting match then it too will suffer the same fate.
Hope this helps.
Steph