The real reason is that I have no idea, regardless they’re attacking a free and open source software project/developers that benefits everyone. Attacking them makes no sense.

Far-right extremists tend to act based on tribal emotions rather than with empathy and logic.
Give them anything as an ‘enemy’ and they’re likely to see red and charge.

Edit:
I remembered the reason:

In the past days, several projects advocating tolerance and equal rights on Codeberg have been subject to hate attacks, such as massive spam of abusive messages in their issue trackers.