I think that to understand the poem Roadside Stand, you have to take into account when it was written. According to this webpage, it was published in the June 1936 issue of The Atlantic Monthly, and I assume it had been written several months earlier. This was in the depths of the Great Depression, at a time when unemployment was around 20%, and the prices farmers could sell their products at were rock bottom. Farmers were having an incredibly difficult time staying in business—banks were foreclosing on their farms, rich investors were buying farms as investments, to sell once the Depression had come to an end, and small farms were being bought and combined into large ones.
I would take this poem as a plea for city folk to help and pity the farmers.
An analysis of the poem follows, including the lines the OP was asking about.
The farmer has just built the roadside stand:
The little old house was out with a little new shed
And the farmer is in desperate need of money:
A roadside stand that too pathetically pled,
It would not be fair to say for a dole of bread,
But for some of the money, the cash, whose flow supports
The flower of cities from sinking and withering faint.
The farmer isn't pleading for a dole of bread—they can grow their own food—but they desperately need money to pay their debts.
However, nobody is stopping to buy anything, even those people who have money:
You have the money, but if you want to be mean,
Why keep your money (this crossly) and go along.
...
Here far from the city we make our roadside stand
And ask for some city money to feel in hand
To try if it will not make our being expand,
The farm family is in danger of losing their farm, in which case they will be out of work and have to move to the city or to towns, where they won't be able to find work and will remain unemployed:
It is in the news that all these pitiful kin
Are to be bought out and mercifully gathered in
To live in villages, next to the theatre and the store,
Where they won’t have to think for themselves anymore,
While greedy good-doers, beneficent beasts of prey,
Swarm over their lives enforcing benefits
That are calculated to soothe them out of their wits,
And by teaching them how to sleep they sleep all day,
Destroy their sleeping at night the ancient way.
What are these "benefits" that they would get? At that time, the unemployed could eat from soup kitchens, and they either had to live on the street or in poorly-built shantytowns called "Hoovervilles" (possibly what Frost is referring to as "villages", although it's also possible he's referring to sleeping on the streets). The soup kitchens were run by philanthropists, churches, and other do-gooders. It's possible that do-gooders helped in building Hoovervilles, although presumably much of the work was done by the inhabitants.
So this part of the poem is somewhat ironic: these "benefits" don't actually amount to that much, and they're "enforced" because that's the only way the farmers can stay alive once they're in the city (assuming the money for they got for the sale of their farm went mainly to pay their debts).
You didn't ask about the last lines of the poem, but I'm going to address them anyway:
I can’t help owning the great relief it would be
To put these people at one stroke out of their pain.
And then next day as I come back into the sane,
I wonder how I should like you to come to me
And offer to put me gently out of my pain.
I assume that these lines were why Frost subtitled the poem “On Being Put out of Our Misery,” and thought of titling it "Euthanasia" (see the website I linked to above). I would guess that Frost had heard some people express the opinion "wouldn't it be great if these people just disappeared and we didn't have to see their ugly roadside stands, or think about their misery, anymore." In the last three lines of the poem, he rejects this idea.