Can't remove Anonymous access

[domenico pandolfino]

Hi. i installed mariadb on centos 7,
i used mysql_secure_installation
i set root pwd i remove anonymous access and test db.

if i digit: mysql -u root -p
it ask for pwd
but
if i digit only: mysql
it let me in without ask for pwd and i can full operate.

i see all users into mysql.user and there is no user=''

how come?