The definition of 'exploit' has very little to do with force. If someone drops $5 and doesn't notice, and I keep it, I exploited their inattention. If there's a forest, and I have a chainsaw/crane/truck, and no one cares if I chop it down, I can exploit their indifference and exploit that resource. If you click on a phishing link, the hacker exploits your carelessness. If the developers of your OS left a security hole, hackers can exploit that (and when they do, it's called an exploit). If you love puppies, the ASPCA can exploit that to get donations. And if you have only a high school education and live in an area with plenty such people, I can exploit that by building my warehouse there, and you'll be eager to work there for minimum wage, and I can exploit that. No guns were drawn in any of these examples.

In most of your examples except the Amazon one (and, maybe, the ASPCA one), the person being "exploited" is worse off afterwards.

You are equivocating on two subtly different definitions of exploit: the bad one where you abuse someone (the hacker exploits your carelessness... to hurt you), and the neutral one (exploiting a resource).

In your Amazon warehouse example, people in the area are better off than they would have been without the warehouse.

I encourage you to see them all in the neutral sense. I intentionally included examples where exploitation can have a positive effect (ASPCA, if you love puppies), no effect (picking up the fiver the person has already lost), negligible or temporarily negligible effect (forest) or arguable effect (Amazon) on the victim. These things are usually not primarily about the victim and how awesome it will be to screw them over. (Except maybe the hacking examples where they might find it fun or funny.) But the neutral use of the word exploit is the one that will come closest to the business analysis being done by Amazon or any other big company. They don't set out to screw people. But they will exploit people, as a resource, to the degree that they're available at a good price.

Anyway I was only here to point out that exploitation doesn't always involve force, not really to argue whether Amazon workers are better off. Couldn't really weigh in on that without surveying them. And I'd need to have a list of criteria in mind, which may or may not match the people's own criteria. (Or I'd have to use their own criteria, which would mean asking more questions and lengthening the interview a bit.)

Off the cuff though I'd say whoever calls a suicide line or 911 because of work issues is probably not overall better off because of that job. (Add the appropriate disclaimers to the effect that those people are presumably a very small minority, and probably have non-work-related issues in addition to or instead of work-related ones.) Also they're not as well off as someone else who got hired at the hypothetical "other employer" with the warehouse in walking distance from their house who pays twice the rate and has showers, free employee caviar etc. (Edit: or just being allowed to take a simple bathroom break with dignity!)

Then there's also the notion (and this is where it gets really hand-wavy) that being a conduit for that money, from your employer's customers to your landlord, isn't exactly the height of joy and fulfillment, as most of us know. Though it does define some basic level of competency in a capitalist economy and being well off or at least better off as you say, than you would with a worse job or no job.

In my opinion, you can exploit people even if they willfully do something for you. For example, in some poor nations people do work that is very harmful, they do it to survive. People put up with amazons policies because they need the job to survive.

What if Amazon kills all the local business and becomes the only employer of people from few villages? They can exploit and use the same logic that you describe.