I grew up somewhere hunting was an important part of the local culture, and I learned to hunt at a young age. We often chose copper bullets rather than lead for performance reasons. A ban on lead bullets would not make hunting meaningfully harder. Copper costs more, but if ammunition cost has a significant impact on someone's ability to hunt, they're doing it wrong.
A ban on lead practice ammunition would have a significant impact, but the article does not discuss that.
My dad has cast his own lead bullets. The equipment to do it is inexpensive and commercially available, and it's easy to come by scrap lead. It's common for hobbyists to add tin and antimony to adjust the hardness.
Copper has a much higher melting point than lead, so it would be more difficult and dangerous to attempt to cast it with hobbyist-grade equipment. I'm not sure if casting copper would produce good bullets; a quick web search suggests copper bullets are made by machining or cold swaging. It would certainly be possible to make bullets from round ropper rods by machining them with a hobbyist-grade lathe, but it would be time-consuming.