I will say that given the recent California home schooling controversy, my conclusion being that California's home schooling codes are poorly written, I don't blame the person in question for not wanting to commit to upholding other poorly written statutes in that state's constitution. And on top of that, you've got California judges who interpret that state's constitution any way they feel like anyway.
Same problems with the federal Constitution.
Still, this seems to be a non-issue issue; a purely emotional reaction to not wanting to sign a pledge.
What am I overlooking?
Vowing to protect the US.