Movies
You're born into a family. You do not join them like you do the Marines.
— Jerry · While You Were Sleeping

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
This draws a contrast between the two ways people end up in a group. You arrive in a family by birth, without applying, whereas you enlist to join the Marines. The speaker uses that comparison to say family isn't something you sign up for.
Context reviewed