I didn't really see anything in the article to make me think the assumptions at the start were wrong, if that's what she was trying to do. Indeed after the initial bit she says
"So far, everything fits with the assumption that women who kill are probably desperate, that some are women facing abuse who are finally fighting back. This is even more the case when we consider that research has found that compared to men, women more frequently kill intimate partners in situations where the homicide victim initiated the physical aggression."
Although she then talks about female serial killers and says "In a US study of 64 female serial killers" but this doesn't tell us what percentage this represents of female killers nor against male ones, other than "Serial killers are themselves quite rare" and then says" but these examples remind us of the need to challenge our assumptions about why, when, and whom women kill." - not really if that's .0000000001%