Let's define radical feminist again, shall we? What does this wordsmith think the root of women's oppression is? Given that the 'radical' in radfem comes from radix which is Latin for root.
Does she maybe think our oppression is because we aren't kind enough? Or that the root is maybe our femininity? What is it that all women share regardless of culture, socialization, personality, preferences, politics, sexuality etc?
It's our sex. That's it. Our physical bodies make us women, and it is the disadvantages of our biology that form the basis of our sex being limited by gendered expectations of the world around us.
That's why we challenge those expectations, that's why we campaign for accommodations and legal rights to spaces for privacy, dignity and safety, away from the other sex who share none of those disadvantages.
Radical feminist doesn't mean extremely feminist. It's not a statement about how very committed we are to feminism.
Words matter, people, and they actually mean things. That's what language is.