Seemed to have missed a major one:

Reason #14: UFOs are actually top secret military aircraft and they
don't want people knowing anti-gravity technology is even possible.

If anti-gravity was possible then it would also be possible to construct
a powerful free energy device simply by blocking gravity on one side of
a huge concrete filled drum. Once the secret got out then millions of
these would be built. They could cause massive stresses to build up in
the earth which would cause massive earthquakes. They would also alter
the speed at which the earth rotates.