>

Billionaires are bad because they own the means of production and exploit the labour of everyone that works for them to a much greater extent than others. CEOs aren’t as bad, but they still exploit their employees and their class interests align with billionaires in maintaining private ownership over the means of production. 
If a working class revolution was ever a realistic possibility, most CEOs would be on the side of capitalism against the working class. They have too much to lose.
Yesterday was CEO jackpot day in Belgium.  Yesterday CEOs of a BEL-20 company made as much as the average Belgian does in a year src.  While CEOs might not be te biggest sources of inequality if you compare them to billionaires they most certainly contribute to it.