I think the designers had the responsibility to anticipate at least some of the more obvious possible interpretations of their memorial, and the association between the Red Crescent and Islam is one of them. This is more than a few paranoid folks "misinterpretting" a design - the design itself echoes a well-known international symbol. The designers had a duty to avoid such an obviously embarassing and painful association, even if the association was unintentional. If they were design students, they would get a "D". Time to get back to the drawing board.
I agree.
As a professional designer I have to always be on the lookout for unintentional design results.
Even shapes that are not immediately recognizable suggest emotions and associations. Every designer and architect worth their salt knows at least a little bit about the psychology of advertising and design, and the impact their use of colors and shapes will have.