I ran out the door after finishing the previous post and belatedly remembered a conversation with a woman who professed that "feminism" is a word that no longer has any specific meaning, and "feminists" no longer refers to any one particular group advocating a common ideology. What somebody means when they espouse feminist ideas, or who they're saying they are when they identify as feminist, is dependent on how they position women's issues (and on which womens' issues—which issues, which women) within the schematic of intersectional identity politics.
Perhaps I don't have the right to opine on this (as a male), but the germ logic of feminism is that women are not second-class citizens and should not be treated as such. That's all I mean when I say "feminism."
This definition is only a starting point. "How should women be treated?" "What do women need?" "How should women behave?" The more rigorously these questions are examined, the more divergence there will be in the answers. But the original statement is uneffaceable and inarguable.
A rephrasing of the earlier point: a progressive movement that allows or encourages the equitable concept of feminism to be obfuscated by sectarian vindictiveness and dogmatism is not doing itself any favors.