That's what Georgeism is?
Henry George was obviously a Single Taxer, but "Georgism" has a generally broader meaning than that. Some Georgists are single taxers, but not all, including Greg and I.
When we talk to elected officials, we don't even talk about Henry George all that much (I did in the ACX article series because it all started with the progress and poverty book review). We mostly speak of "Land value return" and our focus is mostly on pragmatic revenue neutral tax shifts to LVT.
They're free to prove me wrong by saying that they're in favour of sales tax or income tax or capital gains tax. That would prove to me that they're just taking the idea that "land value tax is good" without buying into Georgeism as a whole. But I'm confident we'll never see such a comment.