Antifa and being anti-fascist are not exactly the same thing. For one antifa is not a group, a lot of different people and groups claim to be part of the movement and they all go under that banner, nearly all are anti-fascism. However, certain groups within the antifa umbrella are obviously more anarchists, some are just anti-alt right, some are communists groups etc. it’s hard to define them. It’s just republicans that have been working overtime to make it seem like it’s one group with a detailed manifest.
That’s why I don’t like when unclear “groups” or movements take names that most sane people agree with, but stand for so much more than the name actually states.