As regards "evil, hypocracy, rationalizationing":We start getting into a definition of emotions with your question. The classical Objectivist one is that an emotion is a subconscious value judgment.
Do you say then, that these evoke emotions; and if so, are one's emotions driving these acts of rational self-interest?
When you encounter evil, vile, loathsome things in front of you, you express disapproval. That is only normal. On Solo, some of these despicable nasty creatures show up from time to time and are normally welcomed and tolerated for quite a while. Different posters pop up to engage them in a polite - or playfully colorful - manner. After a while, they start showing their true colors and start offending those who do not buy their snake oil.
The offense can be polite or it can get really vulgar, but it is mostly vulgar. There seems to be something that irritates the hell out of a person with a hidden agenda when he/she is consistently not agreed with on rational grounds (or even consistently not agreed with at all).
In some cultures, these disgusting sorry excuses for human beings are tolerated. In others they are politely ignored. In others, they can make a nice little clique for themselves. Here they are called fucking assholes and the fun starts.
Linz occasionally coins phrases - one of which is weasel words. He holds that expressing disapproval for evil is good. Tolerating evil is evil. Words that tolerate evil he calls the infamous weasel words. His phrases tend to be artistic and include a dose of rat poison (like the term Saddamite, for instance). (He also coins nice terms too, for instance, NEM, which is "men" run backwards and means "New Enlightenment Man.")
Evil is the only thing that benefits from too much tolerance. The good never does. So disapproval of evil is actually in the interest of the good.
Balance is always a sound idea before deciding to draw your six-gun, though. But once you draw, you gotta start shooting - since fucking assholes tend to shoot all over the place without mercy. That is what happens here.
Balance (before trouncing evil) at Solo is shown in the initial tolerance and welcoming of a new poster. It is also shown by the benevolence you can feel all around you and by the phrase "agree to disagree" that pops up from time to time between posters who respect each other. Just look around here for a while and you will notice several other attributes that create this balance. The people around here are pretty darn nice most of the time.
If you follow some of the threads, you will see abrasive exchanges develop like I mentioned - tolerance of poster, explanations and discussion (where disagreements tend to be blunt at times, but generally respectful), offences made by poster, increasing irritation and then explosion.
Where you don't see this, where foully trouncing a poster seems to come out of nowhere, there is usually some kind of ongoing history in place. If you go to the poster's profile, you can check out some of his/her earlier posts and almost certainly you will discover this pattern.
Do mistakes get made? They certainly do. That is why you apologize. I can think of several posts where Linz has done this for an excessive reaction. He, to me, is a big man with a big heart and a big mind. (OK, Linz, I'm done with sucking up or a while... //;-)
Among people of good will, apologies are accepted, behavior is changed (at least about the idea in question), and respect on both sides is increased. You can always spot a non-benevolent person, or one with a hidden agenda, by his/her steadfast refusal to apologize to anyone under any circumstances. What a sincere person values more than anything else in a community like Solo is to share rational understanding - including how he/she feels about it. If it takes an apology to clear up a misunderstanding and get there, I have seen not one of those I fully respect refuse to proffer one.
Now to the crux of your question. Is this in rational self-interest? Once again, the answer is yes. Reason without emotion leads to anxiety and/or apathy. Letting off steam (both good and bad) for the right reasons is extremely healthy. (There is even a theory that it can help you avoid diseases like cancer.)
Since an emotion is a subconscious value judgment, what good is it to make a value judgment if you cannot express it? Mentioning a conscious value judgment in a polite manner can satisfy. But subconscious ones need a bit more elbow room, as they get really rowdy at times.
Solo makes room for them. Solo is an environment where rationally based emotions are fostered.
Not perfect, maybe. But it is sure a hell of a lot better than anything else I've seen so far in Objectivism.
As a member of Solo, you have my personal invitation as to do the following. Look around. Read, skim, analyze. See what makes you feel good and/or bad. Think about it some. Then let it all hang out.