Imagine if there's a club where people dance. It's great fun, but the club is owned by a single person. That person has the final say in all decisions: what dances are allowed, which clothes are acceptable to wear, which food you can bring, etc.
This is often good: it is an easy way to avoid people bringing stinky food to the club, ruining the experience for many others, or people dancing in a way which might make others uncomfortable.
However, that person (and the person helping them, either employees or moderators) is in turn also able to make decisions which aren't very popular, like suddenly requiring an ID check to get into the club.
Some people who wanted their dancing not be directed by person disconnected from their life then went ahead and made their own club. But the question was: how can they avoid that they become like the jackass who wants to dictate how people dance?
The answer: federation. People can use their membership in those new clubs at other federated clubs, enabling them to freely check out other clubs without any hassle.
The customization and community aspect is a nice side-effect: there are now clubs focused on e.g. classic dances, who might go for a more classical design of their dance halls or have a certain dress code.

[Reddit, Twitter, etc.] => [Fediverse]

Plain food => food but you get to choose (which) spice(s)

Plain dancing => dancing but you can choose which clothes to wear while dancing

Plain grammar => talking but you can choose a dialect and or accent

Plain cat => you can choose which cat you like from an animal shelter

Though they all fundamentally revolve around platforms that enable sharing content, the main difference usually is, at least to me personally, the interface through which you access the content.

Can't think of (good) analogies for lawsuits, sadly don't know enough about nail polish, and it's too late into the night for me to think about biology.

It's also too late for me to see if what I said made sense or is plain bullshit