>Are we just bored and desire entertainment and drama?
Essentially yes, We evolved so that we get a chemical hit when we engage with social drama. If you are bored, have nothing better to pay attention to, and/or have low self control, it is a very easy way to get a quick fix.
>What's the evolutionary drive for drama anyway?
Humans evolved as pack animals, paying attention to pack drama was extremely important. Picking sides or paying attention could mean the difference between getting your next meal or being beaten to death.
Because we evolved in small packs, where information was usually relevant, we don't have a good filter, or on/off switch.
Today we are exposed to the latest and most exciting drama from around the world, opposed to our tiny pack, and it is really hard to resist paying attention.
Paying attention to anything in the news or on social media is unlikely to make an impact on your life. Even the biggest topics have a very low risk of impacting you personally, but you will notice that most of them have an explicit or implicit hook that they could impact you.
People want inflammatory content like a moth wants a flame. Facebook amplifying a signal from the lunatic fringe preys upon the need of non-lunatics (or different-thinking lunatics) to argue against ideas they consider dangerous or just wrong. As a side-effect, it makes the ideas appear more mainstream, which has the effect of making the ideas more popular. This further increases the compulsion of non-lunatics to address the ideas.
I'm not sure if that qualifies as being what people 'want' or not, but it seems like it's profitable.
Facebook prioritizes what people want to see, and people want to see train wrecks and inflammatory content.