(and yes, sometimes i do have connection blackouts but i am at work when that happens most of the time, or i go to a location with my (gaming/3d editing) laptop where internet is not an option or very limited) So, now curious, i disconnected my WiFi for once and tried to make a lobby and indeed i cannot make a 'private, visible to nobody else' lobby without an internet connection, you just get tossed back to the lobby screen unable to play even the tutorial. I'm not amused by that idea, but it is as it is.'
You still need a network connection to open a lobby, even if only for yourself. Expecting it to be single player, as in offline game, is a false assumption.
'The bots are there to help a lone player or skeleton-crew operate the boat.