If those white people were part of a religious movement indiscriminately targeting the larger society, then of course they would be labeled "terrorists". Do you have an example of where I'm wrong?

calling the president a terrorist

If you'll recall, the White House referred to the GOP as suicide bombers over debt ceiling negotiations. That's political posturing when either side does it and has little to do with legitimate use of the word "terrorists" in the context of labeling organizations seeking to maximize loss of life and destruction through surprise attacks on civilians.