You know how in a bureaucracy heavy industrial workplace even the most distant of "near misses" gets the book thrown at it even if it doesn't make sense.
Well flying is like that kind of workplace but cranked to 11.
Right, but if an engine is going to fail... it’s going to fail. Whether it’s over land or over sea, it’s going to fail. I haven’t heard of anything saying jet engines are more likely to fail over the open ocean. So that plane would be diverted anyway, even if the failure happened over land. The only difference in risk is how far the plane has to go to find a runway they can land on, which still can be a problem over land because it’s hard to safely set a 747 down in the middle of the Congo or the Amazon or Siberia or northern Canada, etc. And even the biggest 787 can land on a shorter runway than even the smallest 747.
Again I’m not a pilot but it seems like diverted planes isn’t the problem, the problem is finding a safe place to set the plane down if a failure does happen. Yes the ocean makes that difficult, but so does a lot of land.
Land can actually make it trickier in some aspects. If your aircraft experiences depressurization, a rapid descent to a breathable altitude is required (how rapid depends on the aircraft). In mountainous areas this can be difficult (but is, of course, planned for).
Well flying is like that kind of workplace but cranked to 11.