>"Monster Green shoppers are likely younger (Gen-Z/Millennial/Gen-X) male, lower income & Caucasian (skews Hispanic)."

What does this sentence even mean?

Companies like Monster and Redbull are marketing companies that happen to sell energy drinks.

That is almost certainly not a meaningless demographic they pulled out of thin air. It might not be meaningful to you as a demographic. It might even be offensive to you as a demographic.

But, to the marketing company, that is a concrete “group of humans” that respond well to their product and advertising. It informs how they develop their ads, how they target them, which geographic markets they push hard in, what events they sponsor, etc.

When they define that demographic as the people they’re targeting, and allocate their capital towards targeting them, they see the highest returns they’ve been able to find so far.

Which part don't you understand?

(Gen-Z/Millennial/Gen-X)

This covers like sixty years?

It means a marketer will know where to deploy capital.

Which part? younger men with lower income who are likely to be Hispanic Caucasian (as opposed to non Caucasian Hispanic)

It means some people still think there are meaningful racial categories, that people with light skin come from the Caucasus, that speaking Spanish is an "ethnicity" which is orthogonal to "race".

Also Gen X (aged between 44 and 60 at time of writing) are "young".