sendmail：在不是这种情况下抱怨“组可写目录”？

sendmail由于Group writable directory错误，我无法启动我的服务：

$ service sendmail start
Starting sendmail: 451 4.0.0 /etc/mail/sendmail.cf: line 87: fileclass: cannot open '/etc/mail/local-host-names': Group writable directory
451 4.0.0 /etc/mail/sendmail.cf: line 596: fileclass: cannot open '/etc/mail/trusted-users': Group writable directory
                                                           [FAILED]
Starting sm-client: /etc/mail/submit.cf: line 552: fileclass: cannot open '/etc/mail/trusted-users': Group writable directory
                                                           [FAILED]

但是，权限似乎是正确的：

/ETC：

$ ls -ld /etc
drwxr-xr-x. 93 root root 4096 Oct 17 14:23 /etc

/etc/邮件：

$ ls -ld /etc/mail
drwx------ 2 root root 4096 Oct 19 16:43 /etc/mail

/etc/邮件/*：

$ ls -ld /etc/mail/*
-rw------- 1 root root   469 May 20  2009 /etc/mail/access
-rw------- 1 root root 12288 May  5 18:11 /etc/mail/access.db
-rw------- 1 root root     0 Jun  8  2014 /etc/mail/aliasesdb-stamp
-rw------- 1 root root   233 Apr 12  2007 /etc/mail/domaintable
-rw------- 1 root root 12288 May  5 18:11 /etc/mail/domaintable.db
-rw------- 1 root root  5584 Nov 11  2010 /etc/mail/helpfile
-rw------- 1 root root    64 Apr 12  2007 /etc/mail/local-host-names
-rw------- 1 root root   997 Apr 12  2007 /etc/mail/mailertable
-rw------- 1 root root 12288 May  5 18:11 /etc/mail/mailertable.db
-rwx--x--x 1 root root  2700 May 20  2009 /etc/mail/make
-rw------- 1 root root    92 May 20  2009 /etc/mail/Makefile
-rw------- 1 root root 58439 Nov 11  2010 /etc/mail/sendmail.cf
-rw------- 1 root root  7202 May 20  2009 /etc/mail/sendmail.mc
-rw------- 1 root root 41521 Nov 11  2010 /etc/mail/submit.cf
-rw------- 1 root root   941 Nov 11  2010 /etc/mail/submit.mc
-rw------- 1 root root   127 Apr 12  2007 /etc/mail/trusted-users
-rw------- 1 root root  1847 Apr 12  2007 /etc/mail/virtusertable
-rw------- 1 root root 12288 May  5 18:11 /etc/mail/virtusertable.db

这里有什么问题？