While I think it's important to not neglect the horrors of slavery and the theft of lands from indigenous peoples, it's disingenuous to imply that the sole (or a major) cause of America's current and continuous booming economy was either of these.

The easiest way to dispel this notion is to show that the vast, vast majority of American wealth (>99%) came about long after slavery had ended. Indeed, if we could return to the economy at the time slavery was in full swing (even disregarding morals), not one rational person would choose to do so. Another way is to compare the US economy to those that didn't discontinue those practices. Or to show that even in current circumstances the US economy continues to grow rapidly, after hundreds of years of doing so.

So, please don't forget the atrocities caused by the United States. But also don't attribute everything that ever happened in the United States to those atrocities. It may be a cheap way to brush aside the success of the United States, but it isn't an honest argument. Clearly there's something else going on that has made the United States the most wealthy country in the world (per capita).