Celebrities have to be careful what they say. The whole world is watching. She may or may not have intended it to come out the way it did, but it was still a comment she did not think through at the time. When people hear criticism of their home, they are going to be offended and they are going to remember.
I remember a few years back, Dylan McDermott filmed something in Alberta, I believe in the Calgary area. In an interview, he described the area as boring, nothing to do, uncultured people, etc. How did he come to that conclusion? And even if he felt that way, why say it? Why not say "I enjoyed my time there, but I am glad to be home" or "I especially enjoyed having the chance to visit the Canadian Rockies, truly spectacular" or "the people were very welcoming and friendly". There has to be something positive one could say, imo.
GP could have easily spoken about how much she enjoys living in the UK without making comparisons to Americans. IMHO