Excellent post. You make a very valid point about the, "my old man/teacher used to beat me and it did no harm, wo I'll do the same".
It quite clearly has done them harm as it has now instilled the belief that it is acceptable for a grown man to hit children. These types of people are a danger to children who need love, support and guidance from the key adults in their lives, not a "healthy sense of fear".
I ask those people, show the evidence and research that proves physical punishment of children has positive outcomes. I'll save you the time. Not a single study has shown this.
Research HAS shown that children who are beaten have increased levels of anti social behaviour, associations with mental health problems (depression, anxiety), slower cognitive development and it adversely affects academic achievement.