Southern secession removed the congressional opposition blocking free-land homestead legislation

Evidence

The Homestead Act was the climax of a long political struggle. Public land policies had long been subject to clashing interests. The land was a cash cow for the federal government, but settlers and their allies wanted cheaper and cheaper land—​and ultimately no price at all. Until 1861, sectional disputes and the slavery crisis bedeviled the issue. In Congress, men like Galusha Grow of Pennsylvania championed a homestead bill, but there was also bitter opposition. Civil War, and the secession of the South, removed many enemies of the homestead principle from Congress. In 1862, as we said, the bill became law. — Lawrence M. Friedman, A History of American Law, 2395