So where does the side loading come from that people are talking about? Gravity is inevitable, and vertical. With the front high, the CG (center of gravity) loading would move a bit aft, but it would be minuscule, and not compromise loading on the levelers.
Lateral loads would be from external forces (earthquake, wind, ??) and would be outside our normal expectations and experience. Although, I do have a friend that experienced significant damage from the Northridge Earthquake in CA while elevated on jacks that collapsed.
I often create drawings from photographs, and the site does seem to slope toward the water, and the MH may indeed be level. I would expect that the owner used the automatic leveling option, and this was it's solution. Is it right, perhaps not, but is probably OK without unusual forces that would not normally be encountered.
I would feel comfortable with this setup, would sleep well, and would very much enjoy the view.