- "Why [MLK]?"
Because it's not just a matter of deeds. It's intentions that matter even more. Columbus was not interested in spreading freedom and equality for all. Such idea didn't exist yet in his time. MLK advocated and defended precisely that, freedom and equality for all.
- "He was a Republican"
David Duke and Richard Spencer are Republicans too. Therefore what
- "His deeds were related to a US segment of the population"
Yes, a segment of the population that has been screwed since time immemorial. Columbus affected the entire world, mainly the segment of the population was already at the top of the heap and open the doors to that group to intensify the use of black slaves. Columbus helped indirectly with the abuse and exploitation of the segment of the population that MLK helped in their final quest for true freedom and equality.