Personally I still use he/she most of the time unless I have a reason not to, but I also try to get into the habit of assuming less, not least because online in particular it is increasingly noticeable how often we assume someone's gender even in situations we have no reason to.
It's not unsurprising that some choose to carry that over into discussing people they don't know the preference of when it doesn't otherwise matter.
One reason to do so may be to explicitly normalise the usage so it doesn't imply a value judgement e.g based on appearance.
That’s some scary sentence here. so gender is now a « judgment ». Like, there’s no reason to assume because steve wozniak has all the physical characteristics of a male, and has always been called « mister », using « he » (which is the grammatically correct way of designing a male human in the english language by default) is the expression of a value judgement... Seeing this kind of mental twist in a scientific forum (which believes there is something called nature, with laws and hard facts) makes me really scared.
I'm extremely sensitive to ideology wanting to change a language to better reflect its theory. It's the first step to totalitarism, and it's almost always done with perfectly good intentions (until we start to see the damaging side effects).
Note that many of the historical examples involve contexts where gender would not even have been in doubt (e.g. all students at Cambridge would have been men).
The use of singular 'they' has been common for (at least) several decades, long before any substantial number of people were worried about trans issues.
But some people use "they" just as a default when they're not sure. Using it as a default all of the time then serves to remove the consideration of whether or not it is done to try to send some sort of signal about the subject.
As a case in point, you here keep talking about Woz, but there is no reason to assume that using "they" was meant to imply anything about Woz at all. As such you're demonstrating exactly why to some using "they" in a bid to normalize it matters.
As for getting scared about it, it's just a pronoun. If that "scares" you, then that is an indication to me of why it is important.
Remember one of the goal of a language is also to convey meaning, and if possible in the most precise way (which is already hard enough even without taking moral issues into consideration).
The only question here is whether using "they" instead of "he" in this case implies something about Woz rather than is just a way for the speaker to be gender neutral in how they are writing about it.
It is already increasingly common to use singular "they" when we don't know the gender - I did it above, when writing about the person who originally used "they" about Woz. The only question then is whether there's any issue with doing so when their gender is relatively well known.
Since singular "they" is already common in English, the only reason why there might be an issue with it in the case of Woz would be because someone concerns themselves with the signalling effect.
We also never use language in the most precise way possible. That is a total strawman. Pretty much everything we write is full of ambiguity, sometimes because easier, but often also very much intentional, e.g. to signal that certain details (such as the gender of the person you're talking about) is irrelevant to what you're saying. And sometimes because it is political, such as to signal that gender does not matter can be.