The phrase "a segment of humanity" is correct and usable in written English.
It can be used to refer to a specific group or portion of people within the larger human population.
Example: "The charity aims to support a segment of humanity that is often overlooked by mainstream society."
Alternatives: "a portion of humanity" or "a part of the human race."
We may suppose that, in ascribing rights to a group, we merely acknowledge the entitlements of a pre-existing entity, but, in reality, it may be the ascription of rights itself that identifies, creates and fixes a segment of humanity as a "group".
To rid the earth of nuclear weapons and to establish an effective regime against violators, a powerful segment of humanity must be organized on behalf of these goals.
How could you ignore -- and even criticize -- a large segment of humanity that's being victimized by authorities, institutionally incarcerated, professionally repressed, governmentally mistreated, educationally stifled, financially subjugated, and socially rejected?
Also, listen to whatever music you want to because there are no rules any more, but be warned: Talking like a rapper if you aren't one and "acting tough" is so transparent and lame that we are considering forming a hit squad to systematically cleanse this segment of humanity.
Our history is a story of continuous struggles to keep the government from sectioning off one segment of humanity as unworthy of the same basic civil rights as everyone else.
Food's various gospels are spreading like wildfire across the small segment of humanity wealthy enough to care about what we put in our bodies and to endow it with a significance greater than mere fuel.
So there can be a significant element of arbitrariness about the segments of humanity that we identify as "groups".
So long as large segments of humanity are suffering chronic poverty and are dying from treatable diseases, organized giving can save or enhance millions of lives.
The decision by manufacturers to ignore whole segments of humanity went unchallenged for decades before the civil rights movement came along and nonwhite consumers started demanding their place on the color wheel.
The Hewlett gift provides the financial base to undertake these efforts, and the development of an exciting new plan for the foreign language and literature departments was an important first step for this critical segment of the humanities.
A tide of humanity is suffering horribly.
