The 90s was just the declining slope from the 50s-70s post war economic boom. But even at the height of that boom, minorities and women were totally excluded. The subtext of "it was stolen from you", the "you" is white men.

Not only were the "good old days" oppressive for minorities, women, and LGBT, but also massive environmental degradation; Monroe Doctrine military adventurism; a government murderously hostile to left politics; all under the threat of nuclear extinction. Frankly this nostalgia is the lefty version of MAGA, and it's frustrating to see progressives looking backward.