A batter has two numbers: balls and strikes. When the batter gets 3 strikes, they're out. If they get 4 balls (pitches that aren't in the strike zone), they walk (advance towards first base).
If a batter swings and misses at a pitch that would normally be a ball, it's considered a strike. If he hadn't swung, it would have been considered a ball.
The point of the video is that at the professional level, batters should be able to tell quickly when a pitch will be as 'off' as the one in the video - so why wasn't the batter able to?
Minor nit: Swinging at a would-be-ball isn't a problem. Missing a would-be-ball is.
Pitches at the bottom of the strikezone, or pitches that are low and drop below the strikezone (that would be called balls) are generally hard to hit, so a lot of pitchers throw sinking pitches there hoping to either get a very borderline strike or a swing and miss.
In this case, the pitch was probably further off than the pitcher wanted, but the pitch thrown is generally less accurate and moves a lot, making it difficult to hit.
For example, when a better has 2 strikes they need to "protect the plate" - swing at any pitch that could -possibly- be a strike (while if they had 0 or 1 strikes, they may let a pitch go hoping it's a ball).
If you're interested in the amount of strategy that goes into a pitchers strategy, I recommend watching this[1] 30 second video of an MLB announcer predicting a pitchers pitches. (Notice the pitch count in the bottom right - "1-2" reads as "1 ball, 2 strikes"
But, the main reason I'm responding is to say that this pitch definitely isn't worse (for any reasonable definition) than a pitch that misses closer to the plate. There are no runners on base and this is the first pitch in the at bat.
It doesn't matter if the catcher catches it or not. It's a dead ball.
He could have thrown this pitch 15 feet over Phillips's head and into the stands and the outcome is the same.
There are also situations where a pitcher will intentionally walk a batter, such as if the batter is very good, so that they can pitch to the next player, who may not be as good of a hitter. There are a whole other set of rules though on how to intentionally walk someone. An at-bat can get complicated with the various ways a batter and pitcher can go about trying to get into the headspace of the other in order to achieve their successive goals.
That can happen, for instance, if second base is occupied and two men are out. Giving a batsman a free run changes that into a situation with still two men out, but first and second base occupied. With first and second base occupied, if the next batsman hits the ball, all three players have to run; that make it easier to get the third out needed to end the (half-)innings.
It also can be done if the man at bat is a particularly good hitter, and the next ones at strike are deemed less of a danger. For example, with third base occupied, it's highly likely that a good hitter will hit the ball in such a way that the man at third base can score a point; that risk is lower when facing a not-so-good hitter. Therefore, the pitching team would prefer giving away that free run and have the lesser player take a go.
This pitch was probably unintentionally bad, but maybe not by much.
That is just a really really bad pitch and the batter is laughing at himself for actually swinging at the thing. He probably thought the pitch was something else and completely miscalculated.
This pitch was entirely unintentionally and laughably bad.