Is one who mocked an actor's beard because of its unkempt and dishevelled appearance considered an apostate, given that he did not intend to mock the Sunnah or the religion?

There is no disbelief (kufr) in ridiculing a person's appearance or dishevelment. Indeed, disliking dishevelment and unkempt beard hair is a common and acceptable matter. The Prophet, peace and blessings be upon him, used to command the grooming of hair and disapproved of dishevelment and unkempt hair on more than one occasion. The resemblance to Satan is not attributed to the beard itself, but to the ugliness of its appearance and its dishevelment.