While reading Lookout Landing to get information about the jerks the Giants are playing, I accidentally stumbled across information that's relevant to the Giants. The article is titled "The Mariners continue to hit the ball hard – and it hasn't mattered", but you're interested in this section:
Yes, there are the Mariners—with the best rate of contact more than 100mph and the sixth-worst non-pitcher wRC+ in baseball. The team they play today, the Giants, hit the ball more than 100mph the fourth-least frequently yet have the third-best wRC+.
Dumbing it down a little: The Giants are hitting the ball softer than other teams, but they still have one of the best offenses in baseball. Mariners fans were already annoyed with you and your team. This just makes it worse.
The article uses the admittedly arbitrary cutoff of 100 mph, so breaking it down just a little bit more helps us out.
Giants rank on batted-ball speed (MLB)
70-79 mph: 5th
80-89 mph: 11th
90-99 mph: 5th
100-109 mph: 25th
110 mph and up: 27th
They're good at lobbing Zito curveballs into the outfield. They're good at pounding Romo fastballs into the ground. They can even shoot more Casilla fastballs around the ol' park. But they're lousy at going Aroldis Chapman on opposing pitchers, and they are almost never, ever going Sidd Finch.
Brandon Belt doesn't hit the ball harder than 90 mph more than a lot of his peers. Same goes with Joe Panik and Brandon Crawford. So what gives? How is this team scoring (please ignore the last homestand)?
A lot of factors, perhaps. The Giants are patient, for the most part, and that helps. Other than Posey, everyone in the lineup can run a little bit. Most importantly, they're last in the league in strikeouts. That's a bad thing when it comes to double plays (4th-worst in the NL), but it's a good thing if it means they're shooting more 90-99 mph line drives around than the other teams. Quantity over quality can be a fun thing.
Maybe the most obvious reason for the Giants' success without super-hard-hit balls is that they don't have any lumbering, free-swinging galoots. They don't have a Giancarlo Stanton or Evan Gattis, a player who swings as hard as he can and figures the rest out later. The Giants have a team of players who hit home runs by accident, not design. Sometimes that's really, really frustrating. Sometimes it's really, really cool.
On average, though, it's working out.
No big, grand point, here. Just pointing out that the Giants aren't exactly smoking the ball, and that's okay. Baseballs are filled with carcinogens, and when you smoke them you do things you normally wouldn't do, like pat other adults on the butt around the workplace with everyone watching and pretend it's totally normal. Please do not smoke baseballs.
And keep doing what you were doing before the miserable homestand, Giants. I'm sure Safeco Field will help you all get on track.