By "propaganda and lies", people mostly mean "things said by the other side". The other side, of course, thinks you're the one spreading propaganda and lies. So unfortunately, what all arguments boil down to is "you should moderate this site to privilege my side and ban the other side". That's not a viable option if we want some sort of shared public space.

The HN guidelines are our attempt to have a set of rules that make some sort of decent shared space possible. We ban accounts that violate them, for what ought to be obvious reasons, so please stick to the rules from now on.