Surely it is up to the individual to ensure that the terminal will remains open overnight? The SEN website is really clear that people can’t sleep there overnight. In contrast STN isn’t clear at all that sleeping isn’t allowed. Their 24 hour operation wording implies that it is.
I get that an 0630 fight means arriving around 0430 and leaving bed significantly before that - 0300, or even before. A hotel hardly seems worth it. But that’s up to the individual - it’s really not the airports concern, or business, where their passengers slept.