Lion Air Max 9's grounded. But why?

 In an abundence of caution, "Indonesia has temporarily grounded three Lion Air B737-9 MAX planes, following an incident last week in which an Alaska plane suffered a blowout that left a gaping hole in the side of the fuselage." But is this justified?

By now everyone knows about the incident. But Lionair is different. It actually uses the MED as a door.

 

In this image a Thai Lion Max 98 is pictured taking off and the full door rather than the plug is clearly visible. Further on the aircraft the seat map shows where the door is clearly marked.