Imho, the concept of rules is just something that we can rely on when actions are taken on people (most of the time) and allows us to ensure a bit of stability but we have to open our minds and see through them. There are a lot of possible situations in which the rules can be breached and yet, this wouldn't affect the community's stability and a lot of possible situations in which no rule would be breached but the community's stability would be affected drastically. But some of the rules are rules and if we want to take actions on people for breaching them, we have to apply the same judgement on every single player in this community.
Let's take a few examples so you can understand my point of view.
1. Language
Let's say that I take the decision to speak French in the forum and that I refuse to speak English. Of course, this wouldn't be allowed even if some people know how to speak French and that I'd be addressing only to them. Why ? Because I could be breaching other rules while communicating in French and the staff that doesn't necessarily speak French wouldn't be able to judge my posts aptly. Therefore, English only is allowed in the community.
Now, let's say that Andrew says something in greek to his friend (like only 2 words). Would this be allowed ? Hell no. This doesn't affect the community's stability directly since he's only having fun around with his friend but we have to ensure that people will respect this rule and we have to show the good example. If we tolerate this situation, it'll be harder to justify the action taken on people who abuse the rule. Therefore, a minimal action has to be taken here in order to ensure that people abide to the rules. Of course, Andrew shouldn't face a forum warning or whatsoever in this situation but a staff member has to give him a verbal warning so people understand that this kind of behavior is not allowed.
2. Insults
Regarding the insults or being rude in the forum, the case is completely different. Why so ? Because we have to be more openminded regarding this matter.
Let's say that I call SychO a retard and that I seriously meant it. Should I be punished for it ? Yes, of course.
Now, let's say that I call Andrew an idiot in forum in order to joke around. Should I be punished for it ? Well, that only depends on Andrew. I know that Andrew wouldn't take this seriously. So if he doesn't take it seriously, there's no need to punish me for it since this doesn't affect anything at all. But let's say that I'm wrong and that he takes it seriously. What should staff do ? Well, that only depends on the staff and on the situation. Most of the time, a forum warning would be issued since insulting people is not something light but a verbal warning can be issued if the offense is not too high.
Conclusion
What I mean is that according to the the rule and the situation, sometimes staff has to be strict and has to take actions, even in the least drastic situations in order to let people know that this kind of behavior is not allowed but sometimes, they can be more lenient and allow people to breach some rules as long as the community's stability is not affected. In this case, that only depends on how things go on and how the situation evolves.
Now, there's not only the rules that should be respected. Even though the rules allow us not to commit the most obvious offenses, there are a lot of situations that can heavily affect the community's stability while no rule is being breached.
For instance, last night someone came to the shoutbox and started criticizing the decisions that were taken by the staff. This kind of offense is heavier than simply insulting a guy in a post since this does heavily affect the community's stability. Even though, RoN remained calm about it and dealt with the situation in a professional way. But this kind of situation cannot be tolerated, specially when it affects all of these at the same time : 1) the community itself, 2) the owners, 3) a specific person.
Cheers.