Jokes aside, The Onion is basically spending a giant pile of money to burn the website down.
Most people thought they were insane. Bill Drummond wrote about how it strained his relationship with his kids. You can tell that he regrets it.
Personally I think a million bucks to lease a domain name for a year is a really terrible business decision. You might be able to argue that it's going to victims but you could almost certainly just park that money into an interest-bearing account and do better for those victims.
But it's also been obvious from the beginning (starting with Jones' own comments) that nobody really gives a shit about these families and they're just props in other peoples' theater show.
Not only would another owner likely allow Alex Jones to continue to operate, but The Onion can truly salt the earth around Alex Jones' business. If they own the InfoWars trademarks... if they own The Alex Jones Show as a trademark? They can potentially shut down Alex Jones' future works if they violate InfoWars' trademarks and intellectual property. They can sue him if he says something defamatory about the new InfoWars. One of the perks here is that The Onion is well-versed in free speech rights, intellectual property rights, and trademark law. They already have lawyers good at this stuff.
The Onion can be a truly significant thorn in Jones' side, the way most other outcomes for this could not. I'm guessing the new site won't be that funny, but thankfully I don't really care about the "art".
If the victims don't benefit from the money now, they can bear their own interest. Time-value, etc.