I'd take the calls to "fight inequality" more seriously if they didn't have such a nationalist tone. 71% of the world population lives on less than $10 a day, if inequality was ended on a global scale the majority of the people out there protesting would see a dramatic drop in income. I have a feeling that isn't what they are talking about.
Based on your comment I assume you are addressing income inequality.
>the majority of the people out there protesting would see a dramatic drop in income. I have a feeling that isn't what they are talking about.
I do know activists that view fairness as such an important virtue that they would be overjoyed to take that bargain even if it hurt their bottom line. However, according to the BBC [0]:
> the world's average salary is $1,480 (£928) a month, which is just less than $18,000 (£11,291) a year.
18,000/365 is roughly 50 dollars a day. According the the 2014 US Census [1] about 18-33% of US households make this or less (18% is single earner, 33% is two earner households). So for 18-33% of the US population nothing changes or things improve.
However, no one has a magic income equality wand. Even if someone did have a magic income equality wand is not clear if the second order effects of global radical income redistribution would be positive and almost nothing would prevent the causes of income inequality from reasserting themselves. For this reason most attempts to fix such inequality focus on the root causes, e.g. differences in the quality of education, disease, malnutrition or structural power imbalances (such as unfairness in the justice system, structural racism/sexism, who gets business loans, rent-seeking, etc...). Almost all of these would likely raise the average level of income rather than just flatten it.
[0]: http://www.bbc.com/news/magazine-17512040
[1]: https://en.wikipedia.org/wiki/Household_income_in_the_United...