There's a thing that happens when you want to improve your English- you let your native speaker friends correct you, like a child- exactly like parents help their children learn a language. It's natural, and it's effective- it's also impossible to have real conversations that way

...because you are effectively in "child mode".
White women have a sort of Bene Gesserit "voice" they try to invoke, a "correcting the help" voice. A "No Maria, there's no time for you to go to church" voice- that a lot of them don't even realize they use in speaking, & writing.

And while they don't realize it- the corrective tone is instantly apparent to many women of color I've spoken to- I didn't given grow up around it, spoke to dozens of white women and then suddenly "why is she talking to me like I'm her foolish maid?".

Oddly enough many *good* women do this, so it's some sort of weird throwback to some interaction they maybe saw their own mothers have, and since their mothers were not overtly racist- maybe were even overtly anti-racist, never realized doing this- is really, really racist.

Some of it even comes from a place of trying to help- a perception that this Woman of Color is going about things the "Wrong Way" (not their way) and if she's gently set right, she'll be more effective (she won't, because she's still not white, and that's the "Wrong Way).

You may mean well, you may think you are colorblind- maybe you are, but a 10-count to decide- is it your place to "educate" this person, is it your place to speak over this person on this subject, and would you speak this way to someone of your own background, is time well spent.