Because it's just outrageous that the company that's still using and refreshing the IP should get to keep it protected, right? Fuck them for managing to successfully keep an IP going for so long.

And let's not act like Disney is anywhere close to the only company benefitting from this. I'm sure DC is very happy not to have Batman and Superman become public domain. Mattel certainly doesn't want to lose the rights to Barbie. Ditto with Hasbro and Monopoly, or LEGO and their bricks.

There are plenty of incredibly long-running properties that continue to be successfully used, refreshed, and reimagined. To me it doesn't seem like some ridiculous concept that they would continue to be protected as long as they continue to be used. But somehow any discussion of trademark law always has to invariably have some "Fuck Disney, amirite?" comment in there somewhere as though it's both completely unreasonable that they wouldn't want to lose the IP they've poured 80 years into or that they're the only company in existence still milking IP that's half a century old or more.