Poor and enslaved peoples tend towards basics: cheap, cast offs, readily available. Very typically, slave owners allowed razors only (for shaving, of course) as they couldn't be used for stabbing (no point, folding, etc.). This was also true of sailors, even though they needed knives for rope work, no sharp 'stabbing' points were allowed. Humans are inventive, if nothing else. Not surprisingly, fighting styles developed around straight razors. This was scary/thrilling to middle-class white folks and many popular (racist) songs were written with razors in the lyric. Example: the LOC has a copy of "Razors In The Air" from 1880 (no composer or lyricist is listed). It was covered by the Kingston Trio in 1961. With typical racisms of the period, razor totin' became the calling card of black folks in song and stories. One of my favorite lines from one of these songs is from "Big Bad Bill is Sweet William Now" (Billy Murray, 1924). The lyric is: "...just shaves with a razor now." It is reasonably difficult to inflict much more than a surface wound with a straight razor in a fight. You aren't stabbing, you're swinging for cuts...slice and dice. Because of the way it has to be held for effective fighting, you don't have much blade exposed in order to maintain control of it. Typical fights weren't about killing, murder is awkward. Cutting someone up was hardly a misdemeanor. Yah, there were many exceptions. Still, a straight razor is awkward to use for deep cutting unless your medium is not moving. A butcher doesn't use a straight razor even though his medium is reasonably still...they're awkward for making deep cuts thru muscle and sinew, not enough pressure can be applied without a fixed handle. A fixed knife, esp a dagger or stiletto is much more dangerous in a fight (which is why they've been banned in many places). However, I would say that training makes the tool. I've always felt that the USMC Ka-Bar is a better entrenching tool than a knife but put one in the hands of a Marine... I carry a 3" pocketknife daily. It opens packages and envelopes and trims my fingernails if I break one, sharpens pencils too. If someone threatened me, it would probably be the last thing I thought about using for self defense. I have no training at all for such stuff. Feet don't fail me now!