...in some southern states, nearly half the White families owned at least one slave.
Which states? This is easier to imagine of e.g. South Carolina than of Tennessee.
In general, exaggerating differences in the interests of different portions of the working class is not to the advantage of the working class. American blacks have suffered more from our racist authoritarian capitalist system than poor whites have, but they have both suffered. Many residents of southern states did not enthusiastically join the war effort; this was why they had to have a "Confederate Home Guard" to brutalize conscripts.
I'm not trying to solve all the problems of the working class (which is not a monolith except when viewed through certain narrow theoretical lenses). I am just clarifying that race-based slavery was fundamental to southern society and economy, and it is ahistorical and misleading to suggest that it only or even primarily benefited a tiny minority of wealthy plantation owners.
The antebellum economy was largely agricultural. A family working ten acres of corn with hand- and mule-power did not in any sense benefit from the fact that other landowners had slaves. It would be more accurate to say that they were in competition with enslaved labor. One might as well ask American factory workers how much they've benefited from cheap overseas factory labor.
Upthread you claimed that such small farmers also used slaves. That may have happened occasionally, but the basic requirements of agriculture in a temperate climate (there is a limited time period during which particular tasks can possibly take place) would have made it rare.
Which states? This is easier to imagine of e.g. South Carolina than of Tennessee.
In general, exaggerating differences in the interests of different portions of the working class is not to the advantage of the working class. American blacks have suffered more from our racist authoritarian capitalist system than poor whites have, but they have both suffered. Many residents of southern states did not enthusiastically join the war effort; this was why they had to have a "Confederate Home Guard" to brutalize conscripts.