Patterns present a method or procedure for making an item. Methods and procedures are not copyrightable. The outlines that accompany patterns are templates for making something. Templates are not copyrightable. If patterns were copyrightable, the copyright would only protect the physical pattern and would not extend to anything made from the pattern.
The issue of the end product being protected by copyright was rejected by the Supreme Court in Baker vs Selden, 101 US 99 (1879), over 130 years ago. There are numerous court cases that reject the idea that a copyright owner can control the use of the copy by printing restrictions on the item.
I have not been able to locate a single court decision where a company has filed a federal lawsuit over the use of patterns to make and sell items. Also, clothing is generally not copyrightable because it is considered a useful item.
Copyrights do not protect ideas but only the creative expression of those ideas.