I find the mind control scenario to be the most plausible.

To stage this little drama, and publicize it widely through the media, would serve two public purposes that I can see:
1) cast even more contempt on the Constitution,
2) make a "Christian" look like a raving lunatic.

This would re-inforce the idea in the mass-schooled, hedonistic younger peoples' minds that the Constitution is no good, and that religious people, especially Christians, just cannot be trusted.
This seems to be a message which the rulers of darkness have been trying to get across to people for quite a while now.

There may also have been private purposes for this act to which I am not privy.

If on the other hand a "spirit" made her do it, it certainly was not the Holy Spirit, but more likely a nasty one from beneath.
I doubt it though.