The nominal configuration of pressurized module hatches on the ISS is open, with the exception of BEAM (Bigelow Expandable Activity Module) which has its hatch nominally closed.

The USOS crew sleeps in NOD2, has their bathroom in NOD3, eats in NOD1, and usually has scheduled tasks ranging from the JEM to COL to the US LAB throughout the day. Opening and closing the hatches every time they entered a new module would take a prohibitive amount of time.

Also, ISS flight rules require that a crew member is never separated from their Soyuz (and now Dragon) by a hatch closure.

The nominal configuration of pressurized module hatches on the ISS is open, with the exception of BEAM (Bigelow Expandable Activity Module) which has its hatch nominally closed.

The USOS crew sleeps in NOD2, has their bathroom in NOD3, eats in NOD1, and usually has scheduled tasks ranging from the JEM to COL to the US LAB throughout the day. Opening and closing the hatches every time they entered a new module would take a prohibitive amount of time.

This example of an approved drag-through configuration provides another example of why hatches remain nominally open. Otherwise all those connections would need to be demated every time a crew member closed a hatch.

(Image Source)

Also, ISS flight rules require that a crew member is never separated from their Soyuz (and now Dragon) by a hatch closure.