Terry reacts to Joey's death like a normal person—by feeling bad. By contrast, Charley and Truck are totally cold. He was a snitch. As far as they're concerned, you don't need to think anymore about it than that.
BIG MAC: We got a banana boat at forty-six tomorrow. If we pull a walkout it might be a few bucks from the shippers. Them bananas go bad in a hurry.
Big Mac's comment shows that the waterfront union is a huge scam, designed to line the pockets of Johnny Friendly and his cronies. They're not staging the walk-out to benefit the longshoreman, but to extort money from the shippers.
JOHNNY: We ain't robbin' pennies from beggars. We cuttin' ourselves in for five-six million a year just on our half a dozen piers — a drop in the bucket compared to the traffic in the harbor. But a mighty sweet little drop, eh, Charley?
Johnny justifies his actions by minimizing them, acting like its not having a huge impact. But, uh, dude, you just murdered someone…
JOHNNY: Listen kid, I'm a soft tough too. Ask any rummy on the dock if I'm not good for a fin any time they put the arm on me. But my old lady raised us ten kids on a stinkin' watchman's pension. When I was sixteen I had to beg for work in the hold. I didn't work my way up out of there for nuthin'.
TERRY: I know, Johnny, I know…
JOHNNY: Takin' over this local, you know it took a little doin'. Some pretty tough fellas were in the way. They left me this (shows Terry a scar on his neck) to remember them by.
Even though Johnny just ordered Joey's murder, he acts like he's a big softie. He also tries to paint himself as a sympathetic victim, bringing up his tough childhood and fights he had with other gangsters. It's quite the act.
TERRY: You know this city's full of hawks? That's a fact. They hang around on the top of the big hotels. And they spot a pigeon in the park. Right down on him.
Terry's talking about birds—but it's really more of a metaphor. People like Johnny are the hawks—predatory, full of vicious appetites—and people like Joey are the soft, defenseless doves, just waiting to be killed.
JOHNNY: Where you guys going? Wait a minute! I'll remember this! I'll remember every one of you! I'll be back! Don't you forget that! I'll be back!
In the end, Johnny is reduced to impotent rage. He's still acting like he's the tough guy—keeping up his act—but since the longshoreman have all turned against him, his reign is over.