WA has what they call destination sales tax. So regardless of where you purchase something, if it’s destination is WA state (you’re a WA state resident and will own/use it), then you have to pay sales tax to WA. Technically this has been the law there for a long time (I’m pretty sure it was the law when I loved there in 2009, or they enacted it soon after). So if you buy tax-free stuff online or go shopping in Portland, you’re supposed to pay sales tax to WA. No one does, of course.
The ruling this year, if I understand it correctly, just enforces state tax laws on online retailers. So every resident of a state with a destination sales tax will now see tax on purchases from B&H and other online retailers who don’t have a presence in their state. That’s quite a few states.
I’m personally going to continue to buy from B&H because I like them. I’ve been happy with them in the past and I like to support small businesses (whether they meet the technical definition or not, compared to their competitors, they’re pretty tiny).