Eugene II cannot back up his point with any video clips or substance, so he dishes out a bunch of flaming nonsense. That's not very impressive from a young former college player who is trying to sell a product.
No doubt that many hitters swing down on the ball. They are the weak or poor hitters that get weeded out in high school or college. The great hitters (the all-stars & high slugging percentage hitters) swing upward at contact with rotational mechanics.
Eugene II fails to understand this key distinction, or Eugene II prefers to believe his own lying eyes instead of the extensive video analysis clips available showing great pro hitters swinging upward at contact.
And why would any person think it would be a sound practice to minimize the amount of time the bat has to contact the ball? Great hitters maximize the contact zone by having the bat on an upward slope at contact to match the downslope of the incoming pitch.
Eugene II, you have video analysis, yet you didn't link us to any video clips showing great pro hitters swinging down to contact. Humm? You would be well served (and most importantly, so would your students) by toning down your comments and spending more time analyzing the swing because you're going way overboard in your nonsense about a downward swing.
PS. You obviously like to write without paying attention or you would have seen the letter from the physics professor on here.