It is probable that those self identification fields are not for the application itself, but for a separate survey, determining the demographics of those applying, or at least it should be.
It is illegal here in the UK to ask for any of that information on the application form itself.
Mind you, I haven't applied for a job in ages, and I am unlikely to do so again.
I just dug up this riveting read;
https://www.gov.uk/employer-preventi...crimination-is