That cap is immediately the clearest example of art in the keyboard community.
That said, the imperial flag choice maybe dilutes your message. I'd err on the side of arguing that nostalgic representations of horrors are different from acknowledgements of their significance (e.g. you could have chosen faded colours or inverted the colours in a macabre representation or used the pattern but not the tones etc.). Yes, juxtaposition with the bloodied face is a clear enough intent, but the overall tone I get from the cap is 'resilience' not 'damage'. And when that is juxtaposed with the imperial flag, you may get some backlash.
This isn't me saying I don't like the cap. In fact, I'm going to try and get it. Art isn't really about trying to avoid being uncomfortable.