This was a weird issue for me. Alpha is WAY over confident. Yeah she has shitton of zombies but we've seen that zombies are literally no threat whatsoever anymore. Even in mass they can and will be handled with minimal casualties. After No Way Out and seeing 10 people take out what seemed to be at least a couple hundred zombies and seeing the Saviors escapse Rick's zombie trap in All Out War both quickly and easily, i was VERY unimpressed with Alpha's threat. She's so sure of herself but I think she's in over her head with Rick. If she tries to test Rick she's going to lose. She's also showing her hand too soon; now that Rick knows exactly what he's up against he can defintely take her. He's got guns, and battle tested soliders. If Alpha has really killed other groups already I find it likely she's never faced anyone like Rick. Her style seems to be based solely on invisibility and surprise, she's lost both those advantages now.
Carl seems like he may have something up his sleeve which would explain his unwillingness to up and leave. I find it a little annoying that he's so attached to this girl but i guess it makes sense... i just always felt he was smarter than that... I'm keeping faith that he knows what he's doing and has at least a half baked plan. He does have a point, this is a little girl who's being raped so often she doesn't even realize it's bad. Her mom is nuts and does nothing to stop it, they wear dead people's faces and she's still young enough to have a life if they can get her away from the Whispers. Carl is morally right in this situation but at least part of his motivation is for the wrong reasons. Still, he's always been a tough and reasonably smart character so i'm willing to give him the benefit of the doubt that he's planning something.
Everyone saying Rick is acting out of character... i disagree. Rick very rarely makes first contact well. He likes to test people and see what they are willing to do before he interacts with them. When he met Aaron he punched him in the face. When they met Jesus they jumped him and tied him up. When he met the Saviors he killed like 6 people. The 2 exceptions seem to be when he met Zeke and when he met The Gov. Rick is also quick to threats and quick to action, always has been, it's how he likes to establish his authority quickly. He's expected to appear tough, especially with so much shit physically wrong with him. Negan tends to be the only person who calls him out on his "tough guy act". So I think it was very much IN character for Rick to threaten to kill that dude just to see how the dude reacted. Kirkman pointed out once that because we've spent so much time with Rick and saw his evolution that he seems more sane when in his own enviorment but when he interacts with other people he comes off as a dick. He says Rick would generally just be this weird guy who's unpleasant to be around.
This post got longer than I expected it to be...
But the headlines of it are basically that:
Alpha is over confident, I think Rick and co can take her.
I think Carl probably has a plan.
Rick has kinda always been a dick to people