The "flip" doesn't occur around 1980, it occurs in the 1970's (feel free to download the excel sheet and examine it yourself, as I did) and it's a trend that follows ALL races, yet the crack era was largely an African-American epidemic.
There was, however, a major social movement in the 60's that encouraged free love, sexual liberation, women's rights, and an explosion of contraceptives. I think this is a stronger explanatory argument, one also made by the Brookings Institution:
https://www.brookings.edu/research/an-analysis-of-out-of-wed...