You made a generalization about the Devil not Mary so the emphasis or presence of Mary does not undo the fallacious logic:
"St John mentions a war between the devil and Mary + saints, therefore the devil is only seeking to harm Mary + saints."
This is the fallacy of hasty generalization. Just because St John mentions a war between the devil and Mary + saints does not mean that the devil is also not leading astray, further perverting and destroying mankind as a whole too.
Actually, taking one point out of the context of a long list of evidence that provides a coherent argument and claiming that one point is the "whole argument" is actually a false "hasty generalization".
Also, changing the point of the discussion is "moving the goalposts".
Bux, I'm afraid you seem committed to misunderstanding me as well as St John.
Since you submit to the authority of the Catholic Church every time you open your Bible and read the Canon of the New Testament you would do well to submit to the wisdom of the early Church Fathers as well.
I will pray for you, Bux, that you will come to know the Queen of Heaven, Ark of the New Convenant, and Mother of All Christians better and that you would be protected from the evil one who does war with her seed.