Even Legislators are Confused
This change serves only to tidy up the statutes. It has been legal for Wisconsin residents to purchase long guns in any state (if otherwise eligible) since the feds removed the interstate restriction years ago. How so? Federal law at one time prohibited interstate purchases of long guns except when a state approved an "adjacent state" exception. Wisconsin did so. However once the federal restriction was removed, the Wisconsin law (and that of many other states) was rendered meaningless. It was an exception to a prohibition that no longer existed. The WI "adjacent state" statute does not prohibit anything. It provided an exception to the federal restriction. That the statute expressly said it was ok to buy in adjacent states did not imply that other purchases were unlawful. What is not prohibited is permitted. The legal maxim/rule of statutory construction Expressio Unius Est Exclusio Alterius is inapplicable. The meaning of and the reason for the statute is abundantly clear. Look at this example:
Federal Law A - It is unlawful for nonresidents to purchase cheese in another state. Notwithstanding the previous sentence, a state may provide by statute that its residents may purchase cheese in a state that has an NFL football team.
State Law 1 - It is ok for Wisconsin residents to purchase cheese in a state that has an NFL football team.
At this point a Wisconsin resident may purchase cheese in Illinois, Michigan, etc. but not North Dakota, Alaska, Idaho, etc.
Federal Law B - Scrap Federal Law A
At this point a Wisconsin resident can buy cheese in any state. The repeal of State Law 1 removes a nonfunctioning statute but doesn't alter the cheese situation. It was not the goal of the Wisconsin legislature to ban its residents from buying cheese in non-NFL states but rather give limited relief from the federal law.