I don't understand what "using people as a means to an end" means here. Sounds like selling something to people to earn money, but that would describe all business.
Yes, because unless there is an alternative proposal to feed and house the 8B people on this planet, then it is a waste of time to complain about the current solution being imperfect.
We don't need M&Ms in the checkout aisle to feed and house 8B people on this planet. Don't conflate what I'm saying with a general anti-business sentiment.
There are many kinds of economic transactions that occur. The best kinds are the win-win transactions. I have an excess of X and a dearth of Y, you have the opposite, and we swap them to our mutual benefit and walk away happy in the long term thinking that we both made a good deal, and even a third party analysis by experts would agree it was a good deal. This is basically the kind of transaction that happens when I swap $2 for a bunch of fresh cilantro at the market, to cook a meal with. Or when I pay a skilled mechanic a reasonable fee to do maintenance on my car that I can't do myself.
Then there's the other kinds of transactions: the exploitative ones. One person substantially and noticeably wins and the other person equally loses. There is no upside for the loser in the bigger economic picture of our lives. Lots of basic examples of this are common, and some are borderline fraud. An example would be the mechanic who charges 10x what he really /needed/ to make a healthy margin, because he's the only mechanic in town and I'm immobilized by my failed car, and I'm poor, and I'm putting it on a credit card because I don't have the money but have to get the car working to keep my job.
I'm positing that, in a larger holistic sense, the transactions for the candy in the checkout aisle (all the advertising that goes into it as well!) are like that. They're not so much economically harmful: it may in fact be a "good deal" in a basic math sense to pay $2 for the candy's ingredients and manufacturing process. But at the end of the day, they're turning a profit and you're continuing an unhealthy sugar addiction and eventually dying of diabetes. It's a transaction that's explicitly designed to exploit you and harm you for their collective profit. This is not a win-win, at least not in a larger, holistic sense.
Let me see if I'm understanding you correctly. You answered in the affirmative that if something is too hard then we shouldn't consider the ethics of it?