The part you're quoting has nothing to do with violence. He's saying most white moderates preferred an absence of tension with black people to an absence of equality. Unless there's something else you wanted to quote it seems like you're grossly misinterpreting what was said so you can call it "advocating political violence" and equate it to what was shared leading up.to the capitol hill riots.

The quotation you provide above isn’t about violence at all. It is one of MLK's many responses to the claim, very common in the 1960s, that African-Americans should not be making big public (non-violent) demonstrations and sit-ins, because this would be too socially divisive. Instead, they should somehow push for change in a low-key manner that doesn’t upset anyone.

I strongly recommend reading some histories of the 1950s and 1960s civil-rights movement, it was a fascinating era. MLK was deeply committed to non-violence, he wrote at great length about why he felt that non-violence was the superior method for pursuing the civil rights cause. It was other African-American ideologues who favoured violent actions, and tension arose between them and MLK because of it.