And banning cares from the city completely would be moronic, causing incredible harm to pretty much every aspect of it. I'm not "so worried about safety" that I would want to destroy the city, and your putting forth a strawman argument implying I am adds nothing to the discussion.
Getting rid of cars entirely may not be practical, but it is objectively true that many more people are killed and injured in car accidents in the same area over any particular length of time you could name compared to subway crime. What is the objective reason why subways are "scary" but cars aren't?
For that matter, what is the objective source for such statements as that stations are "getting dangerous enough" or that "people are avoiding them"? Is any of that backed up by actual crime statistics or ridership numbers, or just sensationalized headlines?