Except that immigrants to the US are a self-selecting group. Only the most motivated people are going to go through all the hassle and work that it takes to actually get here, so of course they are more likely to be successful once they do. There are also a lot of successful black people that grew up poor. But there are just a lot more black people overall, and as a group they didn't choose to be here in a country that is constantly shitting on them. As to your claim that there is no oppression any more, that is constantly disproved by studies that show having a "black" sounding name will result in fewer job interviews, less support from university faculty, harsher law enforcement treatment, etc. It is a reality that you cannot deny.