When is Political Art Acceptable?

I did my first political art work this past week and was shocked by some of the reviews and shocked by myself. My assignment in my VIS 165 class was appropriation. I have always been fascinated by gentrification and ultimately its foundation immigration. I wanted to some of the most densely immigrant populations in the world and compare and contrast them. Where is it seamless and where is there cultural collision.  I received mixed reviews most commenting on the form rather than the content. Some not even understanding the content. I found it most fascinating when people where not able to identify the flag and tried so hard to distinguish different nationalities often putting them into broad sector. So when is it appropriate to make a political piece and where is it appropriate to display it. Here are key things I learned:
1) DO YOU RESEARCH 2) double check wikipedia 3) be senstive to material you aren't all encompassing 4) know your audience and how they can relate, understand, digest the material

Here is my project: (do not copy for your on use)

SO WHEN IS POLITICAL WORK ACCEPTABLE AND WHEN DOES IT CROSS THE LINE?