Society did not get abruptly and dramatically unequal between 2013 and 2015 nor between 2019 and 2020. Socioeconomics doesn’t predict these crime surges.
Richard Rosenfeld speaking to The Guardian: “The only explanation that gets the timing right is a version of the Ferguson Effect”
Vox reporting on Travis Campbell’s research: “Campbell’s research indicates that these protests correlate with a 10% increase in murders in the areas that saw BLM protests”.
Harvard’s Roland Fryer and Tanaya Devi found that prominent BLM protests were associated with 900 excess homicides in the 5 cities they examined and 34k excess felonies. They report that the leading hypothesis is a change in policing activity, and the cities they studied had precipitous drops in the quantity of police-civilian interactions following the protests.
These are professional criminologists and economists—I doubt they’re being “silly” as you suggest.