He can't do that. I don't think you're getting the significance of his words to Michonne. If he "goes after Negan" he and all of Alexandria are dead. He can't handle seeing his friends and family die anymore. He blames himself for the deaths of Glenn and Abe and can't get anyone from Alexandria in any more trouble and risk it. Carl, Judith, Michonne, Daryl... all dead if he hides weapons and uses them when he wants to "go after Negan". And that will be because of him, just like he blames himself for Glenn and Abe dying.
He can't just escape somewhere "far far away" either. You saw the season 6 finale. The Saviors are huge and were one step ahead of Rick the whole way until they got them trapped.
He doesn't have the numbers right now. He knows it, and he's not risking ANYTHING because it puts those he cares about the most in danger and he can't deal with it anymore. He can't watch someone he cares about die because of his actions again.
Rick still thinks about Shane, his former partner who slept with his wife and tried killing Rick so he could take care of his wife and son, and takes care of Judith, who he knows is Shane's baby. Rick killed Shane. Imagine how he feels about Glenn and Abe. Whether responsible or not, in his mind, he caused it.
Again, there is no sense behind the things the writers are making Rick do.
His whole motto was "I don't take chances"
Then he is suddenly out attacking the outpost of some group he never takes the time to scout and learn about?
Running around in a forest with a pregnant lady on a stretcher when the Saviors are after you is another bad idea that makes no sense for Rick to have made.
Making him too "broken" to think about hiding his weapons is the trifecta of silliness. Dude had to kill his best friend, watched Herschel get his head lopped off and ate a dudes face. They even reinforce how crazy he became by showing us the video, but somehow Negan's violence is too much for him?
Negan is now threatening to kill someone if they don't get him something interesting the next time he comes, and Rick now has no way of protecting anyone. Like he is suddenly too stupid to know Negan would be like that... right...
And Negan doesn't have more than a couple hundred guys if that. There isn't enough manpower to watch over all of these colonies and stop people from leaving. There is no way in hell they could realistically stop Rick's crew from leaving and heading out to another state or wherever. If they followed them, use the rocket launcher... derp.
The whole season finale with them cutting off every road was unrealistic as hell. Please.