Agreed that consistency is very important. However, I think that your #3ers, even though they correctly push their system very hard, are actually behaving in a very irrational way.
Being willing to let inconsistencies slide (as the #1ers and #2ers do) violates the important rationalist rule of noticing when you are (or ought to be) confused. However, it's a much less dangerous response than chasing down confusion but refusing to let the results adjust your moment-to-moment world model! In other words, #3ers are only doing the first half of a scientific or mathematical process, which eliminates most of the benefit, but still is enough to give them a false sense of confidence in their own assertions.
The "fuzzy" thinkers, #1 and #2, are just sitting back and letting society guide them along the path of least resistance, often acknowledging (particularly in the case of #2ers) that they have only minimal confidence in their own knowledge. That's not particularly rational, but it at least isn't actively pushing things in a bad direction.
I guess to put it another way: not all changes make things worse, but anything that makes things worse must be a change. The volume of choice-space that makes the world a crappier place is much smaller than the volume that makes things better. Because of that, overconfidence can be much worse than underconfidence, though both are bad.
People who grow up believing certain things,
even if they later stop believing them,
may not quite realize how the beliefs sound to outsiders...
(SCENE: A small cottage in Nazareth.)
Joseph: Mary, my dearest fiancée, there's something I've been meaning to talk to you about.
(Mary's shoulders slump. Slowly, as if under a heavy burden, she turns around to face Joseph.)
Joseph: You seem to be getting fat around the waistline, and throwing up in the morning, and, er, not getting any periods. Which is odd, because it's sort of like -
Mary: Yes! I'm pregnant! All right? I'm PREGNANT!
Joseph: How is that possible?
(Mary's shoulders slump further.) Mary: How do you think?
Joseph: I don't know, that's why I'm asking you. I mean, you're still a virgin, right?
(Mary looks up cautiously, and sees Joseph's face looking blankly puzzled.)
Joseph: Well?
Mary: God did it.
Joseph: You had sex with -
Mary: No! Haha. Of course not. I mean, God just snapped his fingers and did one of those miracle things and made me pregnant.
Joseph: God made you pregnant.
Mary: (Starts to sweat.) Yes.
Joseph: Mary, that is just so... completely...
(Mary's eyes squeeze shut.)
Joseph: ...COOL!
(Mary opens her eyes again, cautiously.)
Mary: You think so?
Joseph: Of course! Who wouldn't think so? Come on, we've got to tell everyone the news!
Mary: Maybe we should keep this between just the two of us -
Joseph: No, no, silly girl, this is way too important! Come on!
(Joseph grabs Mary's wrist and drags her out of the house. SCENE: The gathering square of Nazareth. A dozen well-dressed men, and the town's head rabbi, look on Joseph and Mary impatiently.)
Rabbi: What's this all about, Joseph? I trust there's a good reason for the fuss?
Joseph: Go ahead, Mary! Tell them what you told me.
Mary: Um... (She swallows.) God made me pregnant.
Rabbi, looking stern, yet understanding: Now, Joseph, you know you're not supposed to do that before -
Joseph: No, no, you don't get it! She's still a virgin! God made her pregnant directly!
(There's a long pause.)
Man #1: So, what you're saying here, basically, is that Mary tells you she's a virgin.
Joseph: Uh huh!
Man #2: And you haven't had sex with her.
Joseph: Uh huh!
Man #3: And now she's pregnant.
Joseph: Precisely!
Man #4: So you think that God did it.
Joseph: What other explanation could there be?
Rabbi: Joseph, that is just so... unbelievably...
(Mary holds her breath.)
Rabbi: NEAT!
(Mary exhales.)
Man #5: A miracle! A miracle right here in Nazareth!
Man #6: Wow! I thought that miracles only happened in Jerusalem!
Man #7: Come on! Let's spread the good news!
(They depart. SCENE: Mary is alone with her friend, Betty, in Betty's house.)
Betty: "God did it."
Mary: I panicked! It was all I could think of!
Betty: So who's the real -
(Mary lifts an eyebrow significantly. There's a brief pause.)
Betty: Ah. So that's why the rabbi went along with it.
Mary: Well, he thinks he's the father, anyway. Why, does it matter?
Betty: It puts some things in a different light.
Mary: Like what?
Betty: The rabbi has been telling all the pretty young girls that you, Mary, are the ultimate embodiment of feminine virtue, and when they grow up, they should be just like you -
Mary: I just feel so awful about the whole mess. What kind of thing is this to have hanging over my child's life?
Betty: You've got to put things in perspective, dearie. You told one little white lie. It's not as if you caused the fall of the Roman Empire.
Mary: But what if the Romans hear about it? I don't want my baby to end up being crucified!
Betty: No one's going to obsess about it that long. In a couple of months this whole thing will blow over.
Mary: I hope you're right...
(Exeunt Omnes.)