"You think "they" didn't have such things before white man came along? Really?"
Guns- No, these were a "western" concept - sure we gave them out to whichever indigenous communities we thought would use them *with* us rather than against us - but we only gave them to the tribes/communities we liked. As a result those with guns found they could decimate their opponents (and in cases where we gave them to everyone; each other.)
Disease - Yes, we gave 3rd world countries a lot of our diseases. Not that they didn't have any of their own - but they had a modicum of immunity to theirs. It was the introduction of western diseases such as smallpox that devastated communities of 3rd world countries who had no exposure.
torture - sure, all humans could inflict pain on each other - but it took people such as King Leopold II to truly show how brutal humans could be. Whilst cutting the arms off people who didn't work hard enough in the rubber plantations could be filed under "brutal dictatorship" (which is, for the most part, how the Belgian Congo was run) I'd say it also fits pretty well under "enslavement" too (although I think we've got plenty of examples of how the west has given Africa slavery).
Colonisation - I'm sure there were conflicts and attempts at wiping each other out amongst local tribes before we came along, but never with the kind of force or scale that we used. The fact that many African nations now speak French or a variation of Dutch demonstrates what sort of effect we've had.
Apartheid - Seriously? You think native africans came up with this?!
Segregation - Not only in places such as the U.S, where Africans were considered to be lower class humans (and not even citizens for a long time) but in Africa as well - In Rwanda the genocide of the Tutsi's at the hands of the Hutu was in no small part due to the efforts of colonists deciding, based on arbitrary physical attributes (which, admittedly, did have some basis in tribal history, but was still no basis on which to decide which people were "better") to decide who would effectively be upper and lower class citizens.
These are things that we "gave" them.
Not reading history books doesn't change history.