You'll notice that all of those state names have an @ symbol after then. That means those categories are actually listed elsewhere in the directory, not immediately under http://www.dmoz.org/Regional/North_America/United_States/Business_and_Economy/Computers_and_Internet/Web_Design_and_Development .
In Regional, sites are listed under the most appropriate (and lowest) geographic level first and THEN by topic. For businesses, that is generally the locality where the business is physically based, not at the country level and not at the state level. Oregon doesn't have a Web Design and Development category so there can be no @link to it from this US level category.
To find the right place to submit your site, find the locality where you are physically located in http://www.dmoz.org/Regional/North_America/United_States/Oregon/Localities/ and then drill down to the right category -- if the locality has a Business_and_Economy/Computers_and_Internet/Web_Design_and_Development category, suggest your site there; if it only has a Business_and_Economy/Computers_and_Internet category, suggest it there; if it only has Business_and_Economy, then suggest it there; and if it has no Business_and_Economy subcategory at all, suggest it to the top locality category.
