The city has a notorious open air drug market within 2 blocks of one of its main tourist attractions at Pike Place. Downtown is generally not a pleasant place to visit.
A few years back when I worked in the Seattle downtown, I used to have a walk around the office during lunchtime. I still remember seeing a drug addict baking what I assume was heroin just a block away from Pike Place Markets. It's crazy
I live near Pike Place Market currently and have for years. There is no open air drug market anywhere nearby. Some people doing drugs, and occasionally dealing to each other, but nothing like what you’re describing.
I lived near there for several years. It’s bad but also highly localized. The extreme downtown core is such a small part of the city. Pioneer square, the waterfront, SLU, Seattle center, etc are all very nearly downtown. Area around the new convention center, the paramount, and 5th Ave theatre are totally fine.