My Cattleman Ancestor didn't seem to have a problem with it.
He owned no slaves at all.
Texas had slaves, but only in limited areas, mainly East Texas, and the Brazos River Basin Areas. I have said it before, but in Texas, the popular support for secession, regardless of what the Ordinance said, was the idea that right or wrong, Texas would determine the future of slavery, or any other matter, for itself. Texas saw interference from the North and resented it.
Those 60,000 men who served from my state, had other concerns than slavery.
I'm not pinning slavery interest upon your cattleman relative or on the other 59,999 Texans in CSA service. I do think they were working against their best interest. A regrettable quality in many southerners was that they resented interference from the north more than they feared the tyranny and exploitation from Richmond. I guess it was better to be a 3rd class person in a southern confederacy than to be a free American is union with the despised Yankee.