Sorry, not a Catholic, so I can't comment on the specific saint...
However, their coopted saint probably exhibits Christ-like characteristics and acts as an encouragement to Catholics to exhibit those characteristics themselves -- love God first and foremost, love neighbor and treat as oneself, persevere in the face of adversity, strive for the fruits of the spirit (love, joy, peace, patience, kindness, gentleness, and self-control...), etc. The coopted Goddess has changed her name and changed her ideals. I think she is a convert.
This is sort of like taking a Geo Metro, ripping out and replacing everything except the plastic/sheet metal shell, painting that another color, and then changing the person to whom the car is licensed. Is it still the same Geo Metro? If so, then we need to tell those Catholics to STOP COOPTING PAGAN GODDESSES, #$%@!