To go all psychological about it - I think what gets us out of bed in the morning itching to get going, is a mission that we are in total alignment with, from our base animal self, to our higher intellect.
For JB, she fancies women, believes women would all be happier if they were lesbians, feels a moral duty to rescue lesbians forced into heterosexuality by patriarchal systemic sexism and misogyny, has a class analysis about how male violence oppresses and maintains the oppression of women by men, feels a duty to rescue all women and girls from violent men.
When a feminist campaign crystallises and aligns her motivations - she’ll light up and have undoubtedly impressive energy and determination.
If it doesn’t light her up (as with anyone) she is “meh” about it.
KJK has different motivations - she is a mother and wants to protect her children, she also feels a duty to speak the truth and make sure the truth is spoken, currently lies are being told and the truth is being suppressed in such a way that children are being harmed. She feels a duty to protect children and preserve our right to tell the truth.
KJK is similarly lit up by this, impressively motivated, and is pretty “meh” about, for example, ending MVAWG as her reason to jump out of bed.
The thing is, KJK also goes on about how much she adores her husband and actively challenges the notion that women are better off without men, etc, and this stance completely disrupts JBs whole raison d’etre. So JB could never get enthused about what she does. In fact, I can imagine them both being very eye-rolly about what the other has to say.
Although these differences explain why they are unlikely to get on board with one-another’s campaigning, it doesn’t really explain why JB is such a twat about it.
I think it is probably just down to a personality thing.