I notice some persons are trying to set some local rules in threads to prevent fact based debates taking place so that they may attempt to present a one sided argument and allow only those that support their side to contribute.
If any posts is fact based, on topic and relevant then it must never be silenced.
No. People can set local rules (within reason). Some people don't want to have a debate regardless of the topic. If you feel your voice must be heard, create your own thread.
That would be only invoked for sales based threads.
There can be no reason for a moderator ever to remove facts based on topic or relevant discussion. It would be entirely ludicrous especially on a board such as meta.
Not true. If I made a thread and said that someone was not allowed to post in it, and he did, he'd get a warning from a moderator first (post deletion), but a ban would follow if it continued. Local rules are relatively absolute. Now, some things are kind of unenforceable, like, if anyone posts in this thread, they owe me money. Or something to that effect, but not allowing individuals to post in a thread is within their right.