According to some admittedly vague accounts, the Taylors moved from St. Louis--where the uncle's art business was headquartered---to London, where they opened a branch office. So for the purposes of clarifying that her parents were not British, it might suffice to say they were "from" St. Louis rather than detailing where they both were born. That's why they've been described that way for years, in many sources.
Here's the obit from the Boston Globe.
It's surprising you didn't run into that information before singling me out as if I'd concocted it. I've never had any animosity toward the RFT, which I read and enjoy. I was hoping you would accord me the same respect by acknowledging that, whether or not you agree with the term "from St. Louis," your crosstown pal Joe Williams wasn't the originating source who deserved a public rebuke.