Personally, I've written MANY answers that were longer than a paragraph, and never received a violation for ranting. For other things, yes, but not that. Ranting is not a matter of how MUCH you type, but HOW you type it - choice of words, phrasing and emotional content. If you can present your points clearly, clinically detached and devoid of obvious bias - there is no violation.
Lying is not essential to avoid insulting others. Simple care in choice of phrasing, again, will prevent that. Truth can be revealed in ways that don't insult the intelligence - OR BELIEFS - of those with different viewpoints.
As to typing 'against yahoo answers staff', again, this is dependent on the wording. Using scurrilous language, metaphors that make inappropriate comparisons with certain animals, or other references that are insulting - is a violation. Can you find APPROPRIATE ways to express your discontent with how the site or its employees function? Of course you can - that is the challenge here. Others do it, so why not figure out how to avoid these violations instead of simply complaining against them?