These are not actually very similar at all, in a way they are almost the opposite.
No one is saying that racial slurs aren't real, people say them with meaning and intention at times. It's the meaning that is really offensive, not the combination of particular letters.
We also all know that sometimes we all know that the same word can be used in a differernt way. You can have an actor in a film , who is playing a role. A child repeats a word without understanding. Sometimes the same word can have different meanings in different places (UK vs US for example) or change meaning over time. There is a differernce between shouting at someone and a discussion in a linguistics paper.
Most adults are very capable of understanding these contextual elements and dealing with them, if that weren't the case, we wouldn't have things like films with racial slurs, because the audience wouldn't be able to look at it as part of the story being told.
When you have the magical language type of approach, none of this matters. A child repeating a word, or a person reading a 200 year old document or even one in another language, has the same effect because it is essentially an invocation.
No one is trying to change the meaning, but all words depend on their context in various ways.
With words like "mother" it's the same. Some places do use somewhat different languages for things like breastfeeding. There can be differernces even in what is thought of as rude vs polite talk. Sometimes small children will call their caregivers who aren't their mothers "mummy". Sometimes Mother can be used as a title for a role. Actors play mothers and everyone knows they have no actual children. No one struggles with the idea that context matters to meaning with this language.
Objections to people changing the word women aren't about any of these things. They aren't even about a natural change in language for one particular word where perhaps another word takes its place. It's about an attempt to suppress the expression of certain facts and meaning.
No one is trying to say racial slurs don't exist.