You might want to bone up on these things before assuming LNG ships are safe because you need some energy to vaporize the liquid.

Try Flixborough as a Google search if you want some idea of how bad one of these unconfined vapor cloud explosions can be.  I worked around refineries some.  People were very aware of how careful you had to be around propane/butane facilities.

If you had a shipping accident that split open an LNG ship you could put a lot of explosive material out pretty quickly.    Plenty of heat in the ocean to vaporize it too.

LNG is heavier than air and will form a low lying cloud near the surface.  Find an ignition source and away you go.

Do I think LNG terminals are too risky?  No.  But this assesment plays down the risks too much IMHO.