|Do you know where your variables are?|
Yes, titles are different. There are a lot more ways that they can fall into the category of "hazard to navigation", which I still find to be a very good phrase for defining what (and only what) janitors should mess with.
Note that I'm not disagreeing with much of the rest of this thread. For example, if a new title is suggested that is clearer than the current title but has no other advantages, then I would leave the title unchanged. Level of clarity is not much of a navigation issue and is also a rather subjective criterion and so should mostly be avoided (shoot for clarity when changing if there are other, more compelling reasons to make a change, of course).
In contrast, a spelling error is often a hazard to navigation (as you noted, it makes the node harder to find in a careful search) and usually isn't subjective. So most spelling errors in titles should probably be corrected. However...
But let's also avoid wrangling over contraversial spelling choices. If the spelling is either common or correct, then leave it be. If what to change it to isn't rather obvious (there being no clear alternative that is both common and correct), then leave it be. For example, just about any pluralization of "regex" should probably just be left alone.
And if the word is spelled correctly out of context (that is, the wrong but related word was chosen), then we are back to clarity so leave it be. So seeing "data" when you think1 "datum" is what 'should' have been used is not a reason to consider a node for title change.
Finally, a brief word on creative control: Let people have it. A word may be mispelt for humorous or other creative effect. And just because you don't get the joke doesn't mean that everyone fails to get it. So before considering a node, try to consider whether there might be some meaning (perhaps a playful one) that is escaping you. If you aren't sure, perhaps you should ask (such as in the CB) or just spend that time doing something else.
That last point is even more important for janitors. If there is subtle meaning, then many will likely miss that and some such nodes will get considered (and get a lot of 'edit' votes just because that is the nature of beast). It is your duty to filter requests against principles and so you might need to unconsider a node instead of editting it.
1 I use the word "think" because I believe it is more accurate even though I'm quite sure that many people who need to hear this advise will be using the word "know" instead.