Wouldn’t both of those scenarios be better outcomes than a meat eater that doesn’t care about reducing their carbon contributions at all?

Better outcomes in terms of what? If we only focus on the environment, then the only thing that matters is total environmental impact. While intelligently choosing your foods may reduce the environmental impact of your diet, naively reducing meat eating alone simply doesn't.

Disagreeing only slightly with Dr. Hannah Ritchie from OurWorldInData (steelmanning the less-meat side IMO), transport arguably counts for J>7% of the environmental impact of food, so eating locally-sourced chicken every day is clearly better than ordering out from the vegan joint every day, especially after accounting for the caloric quality.

I asked the previous commentor for takes on the specific scenario to start to depolarize her position. Many vegans here have this polar position, and won't stand beside me as an environmental advocate because I don't agree with them on quitting meat being a necessary or even good environmental decision. Challenging her with the decision of what's environmentally right and what's "morally right" (to her) is a form of deprogramming. It usually fails especially online, but I still do it.

You perhaps can see why it is important to help give and get context from people in that situation?

The strongest environmental advocates I know are small-town farmers in rural-but-liberal areas. But approximately zero of them are vegans. I still want them fighting for the environment.

EDIT: I saw your update. The irony is that your graph comes from the same article I was referring to myself. There is an argument in the vacuum if you focus on beef-herd and lamb only (but you have to understand those are world averages and the methane production from cattle in most countries is a lot lower than that number)... but I'd like to point out that 1kg of poultry is simply a superior food product to 1kg of rice. Eggs are arguably the perfect food for those not allergic to them (like me). Replacing many crops with egg-laying chickens is a no-brainer from that graph (and sorry, but you DO get some chicken meat in every egg coop if you're being efficient).