You are right, firstly, African Americans are real Americans (!!!) who suffer discrimination and the comparison with Europe current issues is not a good one.
Regarding Muslims in Europe, it is actually a very complicated issue. I am really sick of the "colonialism" invocation by our politicians all the time (and at the same time they are conducting wars and breaking apart African countries!!! Talk aout hypocrites). I don't think colonialism is the reason why some French young people from Arab or Muslim families have develop a feeling of hate towards France and are turning to EI (Daech). Reality is, their parents, the first generation, the one which could have suffered colonialism was happy to find work in France and have a better life here, just like my parents were when they escaped Salazar dictature. My own parents had to live in guettos, real guettos, just like the other immigrants. But no one never talk about that an they never felt they were victims. Portuguese (and I am sure Polish, Spanish, ec.) suffered racism an social discrimination too and had to live in awfull guettos as well. Young French people who were born of Portugese parents are acually the less represented at University... they are the ones with the less diplomas. What does it tell us? The fact I did long studies and a prestigious preparatory class is actually not "normal" regarding what the stats tell us about French from Portuguese background.
Is colonialism a crime? I think we can say it is now. But then we have to also consider new forms of colonialism that may be impacting Europe. I am saying that a bit in a provocative way of course, though...