I was only 14 and not very politically savvy when King was killed. In the many years since, I have come to admire him as a great American and activist for civil rights. He advocated non-violence, but never advocated accommodation or surrender. He was in it for the fight.
The sins of white America are many, going back to the beginnings of slavery and on to its awful offspring: Jim Crow, de facto segregation, and racial discrimination in so many areas of life. What is not understood by racists is that by trying to diminish others, they only diminish themselves. Slaveholders fought for freedom for themselves but bondage for others. The cruelties of slavery and Jim Crow only revealed the shriveled souls of the perpetrators.
We have made strides toward equality since the 60s; some have been large - it is illegal to proclaim discrimination; some have been smaller - young people today are much more comfortable in mixed-ethnic groups than my generation. Or that may be actually the other way around. It's easier to pass a nice sounding law than to actually effect change in society, but they are linked.
There is a place for white guilt - white America has been guilty. White America should be proclaiming: Forgive us, we know what we have done wrong, and we are trying to make amends.