Aren't you jumping the gun a little bit? While it's a valid question, it's very premature.
The GDPR does not apply "in the course of a purely personal or household activity and thus with no connection to a professional or commercial activity" [1].
However, that does not extend to generally sharing the information on the internet [2] as that's no longer purely personal.
[1] https://gdpr-text.com/read/recital-18/
[2] https://law.stackexchange.com/questions/92229/what-does-hous...
What's weird is there seems to be no such exclusion for personal information which does not relate to special categories.
Having this 'opt-in' certainly seems to tick the box for consent.
However, if reproducing information from a publicly available bio would fall foul of GDPR requirements, then I think there are bigger fish to fry than a hobby project made by a guy who at least seems to trying to respect people's preferences.