But, you also have to deal with the ball going up and down, side to side (which it does a lot more severely than in Baseball) and different angles the bowler can bowl from.
I'm saying that a pitcher has a lot less choices to choose from when he's deciding how to throw the ball.
And I'm arguing that it's easy to hit a vanilla ball at just below waist height, with no spin or swing about it. That's what you're baseball player was doing in that video. If you add swing or reverse swing to the equation (If you hadn't noticed, I'm trying to bait you into asking me to explain to you the physics of swing and reverse swing. Not for arguments sake, I just think you'll find it interesting), drift, spin, or cutting, all of which are in common use in cricket games, then you'll find that hitting a cricket ball is perhaps not as easy as baseball. Even if it's not as hard, and you can't really prove it either way, it's definitely close.
Ok, your sister plays softball. Try and get her to pitch with her arm completely straight, and see if she can get the same speed she usually does.
On a side note, after some research I've realised that the speed of delivery is about the same in both sports. The fastest cricket bowl was 100.02 mph, whilst the fastest baseball pitch was 100.9 mph. Also, apparantly cricket balls are heavier. A baseball has to be between 5 and 5.25 ounces, whilst a cricket ball has to be between 5.5 and 5.8 ounces.