Both answers may be right, because the collective noun works differently for different generations.
If you’re talking about recent generations, you might refer to the Baby Boomers, Generation X, Generation Y, the Millennials and Generation Z. When you do, you probably say ‘the Baby Boomers are’ but ‘Gen X is’. In other words, you probably use plural verbs/pronouns for one group but singular for another group. This inconsistency is an example of how you may flex your rules to ‘sound right’.
So, given we’re fans of the US Associated Press Style Book (a go-to source for language style trends), we’re interested in a Style Book editor’s response to this exact question about generations. The editor simply referred to the Style Book’s general guidance on collective nouns: ‘nouns that denote a unit take singular verbs and pronouns: class, committee, crowd [etc.]’.
We wouldn’t apply this guidance to Baby Boomers and Millennials, which clearly need plural verbs/pronouns. We’re even troubled about applying it to Gen Z, because these young ones (the generation born somewhere from the mid 1990s to mid 2000s) are also called the Plurals (seriously!). So, when talking about the Gen Z collective noun, if you want to say they are the hope of the future, then feel free.
If nothing else, we have to be comfortable with our language, and this variation on the collective noun rule feels a snug fit.