Feminism is a movement that stands behind all women being equal to their male peers. This equality is mostly fought for within the workplace for equal pay, in the government for equal rights, and in society as a whole for equal respect. However, feminism has an issue with hypocrisy.
While the ideas behind feminism are rooted in creating equality, there are several sects of feminism that are still exclusionary. Some are white women who actively ignore issues that affect people of color or the Black Lives Matter movement, while others are able-bodied individuals who ignore remarks of their own that are ableist or harmful in general.
Though there is a significant amount of privilege women ignoring issues that feminist should fight for, there is a branch of radical feminism that has hypocrisy not from ignoring issues. Rather, this group is actively working against another group of women who, just like all women, need feminism and should not be actively excluded from the movement.
TERFs, or trans exclusionary radical feminists, are a self-described group of individuals who feel that feminism only belongs to those women who are born with vaginas. These women are typically also aligned with white feminist belief systems of ignoring intersectionality and denying problematic behaviors.
An issue with TERFs as compared to white feminists is that they are self-described, happily admitting to being transphobic. White feminism is usually based on systematic oppression and denial of racist, homophobic, transphobic, ableist issues with their movement, while TERFs are active in keeping transgender people out of their movement and women spaces as a whole.
The obvious issue here is that feminism isn't only for cis, able-bodied, straight white women. Trans women need a community and safe spaces as much, if not more so than cis women. Though, this should go without saying, trans women are not in women spaces or part of a feminist movement solely to prey on cis women.
Women who weren't assigned female at birth are not men. Those who insist that they are and that trans women are predatory are only alienating their sisters in the feminist fight. Feminism needs to include everyone since the end goal is equality among those of all varying backgrounds. Excluding even one group from feminism is against the progress that wants to be inclusionary for all.
Again, TERFs and white feminists, while there is definite overlap, differ greatly in their intent of exclusion. White feminists choose to ignore and deny problematic behavior, while TERFs are active in their oppression and exclusion.
Excluding someone due to their assigned gender at birth from feminist space is not okay and anyone who disagrees with that statement is not a feminist working in the correct direction for progress. Feminism is working together and accepting all of those who need feminism or who support the idea of equality.
A vagina doesn't equate womanhood or the value of a woman, seeing as there are several individuals with vaginas who aren't women and women without vaginas. Equating the two things isn't only arbitrary, it's against the core ideals of feminism.
Transphobia and trans exclusion have no place within feminism.