I think the reason for your confusion is that ‘KF’ and ‘FWR’ aren’t single entities and thus don’t have an official, unified stance on anything.
Thus there are posters here who hate KiwiFarms and there is also a significant number of us who see it as a beacon of Freespeech (albeit a beacon that shines out of a cesspit!).
There are also many FWR posters who have learned the value in not ‘cancelling’ someone for something they may or may not have said, especially if that thing was said a decade or two ago.
The main thing the two sites have in common is that both Mumsnet and KIwiFarms have founders who are committed to the concept of Freespeech.
One is subjected to much more restrictive laws than the other and one is a reliant on a more mainstream funding model, but at the base level they exist because the site founders wanted people to be able to exchange ideas freely, even (and perhaps especially) unpopular or unpalatable ideas.
Josh wouldn’t give up his users data without a court order (and Josh advises all sign ups to give as little personal data as possible so that even a court order won’t identify them) and neither did Justine:
https://www.bbc.co.uk/news/uk-england-47894932
(and as it happens, all MN had on a ‘alittlehelp18’ was an email address, an anonymous email address that seemed to reference the person who was making the legal demands to see it)
When you see a FWR person defend KF they are generally defending Null’s commitment to Freespeech, especially as he has been a tiny David constantly forced to battle giant, crossdressing Goliaths, which is something British terves have plenty of shared lived experience with.
Listen to Josh describe KF in his own words via a podcast or something- I’ll dig one out for you if you like.
There are plenty of threads on KiwiFarms documenting the weirdest characters of GC world, btw, it’s just a lot less prominent than similar documents made of TRA world (because far fewer of us are involved in shady business/have closet skeletons to expose/post attention seeking selfies online). We’re collectively too dull to be infamous LOLcows, basically.