Why does Hibernate not delete mappings for a many-to-many join on updates

Question

There are two persistent entities - User and Role. They are mapped by a many-to-many join. The User entity -

@Entity
@Table(name = "users")
@Where( clause=" deletion_date IS NULL ")
public class User extends AbstractEntity {

    private static final long serialVersionUID = 122622094779798680L;

    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinTable(name = "user_role", joinColumns = {
            @JoinColumn(name = "user_uid") },
            inverseJoinColumns = { @JoinColumn(name = "role_id"})

    private List<Role> roles;
    @Id
    @Column(name = "user_uid", unique = true, nullable = false)
    private String userUid;
...

It is an obvious ask to update the set of roles for a user in this schema.

Example - Remove/Add some roles from a user

Addition of roles is fine. But when a deletion of some roles is made to the user entity, the mappings in the join table created by hibernate is not purged.

How to get this purged on role removal?