He's definitely a squatter. If you own something and you don't use it, you're a squatter. I own an old original Nintendo that I haven't used all year. That's why if someone comes into my house and takes it, it's my own fault.
There's an agreement between Twitter and each user. And depending on the name used, Twitter users have own rights too, trade marks and of course domain names are examples.
Let's not confuse digital "property" with physical property. It's disingenuous at best, flat out wrong at worst. On top of that, you don't own a Twitter handle, or for that matter a domain, you rent it.
I understand it was a sarcasm, but there's one difference between the two. A Twitter handle or a domain name is something unique as opposed to a game console of which there were millions of copies.
So if I have a unique object that I don't use or look at or whatever one does with unique objects (say, a piece of art or something), I'm a squatter and its perfectly ok for someone to take it away from me?
Too bad then for the company named "N." They'll have to go with N_company or N_inc or N_co or get really creative if those are taken. There's probably only like 500 names they can choose from relating to "N."