While I agree they have been fairly forthcoming since release, I disagree on the time table, mostly because I disagree with the fact that it was released in such a state to begin with.

Given the abundance of cross browser issues, I can only surmise that cross client testing wasn't done.   Given some of the color issues (dark text on dark background) leads me to believe next to no QA was done prior to launch.

Since the site had clear functional issues, most businesses would have 'rolled back' to a previous version of the code base.  That however assumes that version control is in use, which based on the above several points I am starting to think is not the case.

As a professional web developer, I do not feel this was up to professional standards.  It would be similar, in fact to any one of the artists here releasing an product half complete, and telling buyers to 'wait while I finish it'.   This is a Production site for a business which only makes money over the web.  If the site is unusable it impacts sales, and since it's the artists respective stores which are selling product, that directly impacts every vendor here.

While staged delivery is a software methodology often used, each phase is typically considered complete prior to deployment.  This deployment was simply not done anywhere near a professional level, and unfortunately it's the vendors who are suffering the fallout.