The block at the end that says voluntary
Race and ethnicity, gender, veteran status, disability. Four questions in their own section, each with an option to decline, and the form says plainly that declining is allowed.
They arrive at the end, they are worded more formally than everything above them, and they read as an official demand in a way the rest of the form does not. Two things about them are worth knowing, and both are printed on the form itself if you slow down enough to read it.
The first: “I don't wish to answer” is one of the answers. It is on the list, not a blank, and choosing it is not the same as skipping the section. The second: the form states that this information is collected separately from the hiring decision. What that is worth is between you and the employer, but the page in front of you says it plainly.
What this tool does with it
It fills these only from what you typed into your own settings, in your own words, and only when the option on the form matches what you entered. Where two options both contain what you wrote, it picks neither, because a widget's ordering is not a reason to record one of them as your ethnicity.
You can leave every one of these blank in your settings, and then the tool leaves them blank on the form for you to decide about in the moment. It has no default and never invents one.