For the same reason the ignominious totalitarian regime of North Korea is called "Democratic People's Republic of North Korea" (DPRK): wizardry (also known as "rhetorics").
Names are powerful. The Sapir-Whorf hypothesis isn't just a hypothesis. The way we name things influences how we think about them, how we categorize them, what base assumptions we make about them without even thinking about it. This makes names a very useful manipulation and influence tool.
If you want to seize power to plunder a country, your terrorist group should really have "People's Liberation" somewhere in its name. It wouldn't do to call it the way it is, for example "Association for the Violent Redirection of Plundering to Me and My Buddies." You'd get a lot less support. It simply wouldn't work that well.
Like most bills, in a truthful universe, this one would be called "Fair Repartition of Pork Barrel & Plunder Act," or something of the sort. But then, it wouldn't pass. It would be hard to defend in the Senate, and even journalists would perhaps smell something fishy.
Therefore:
Why is the Inflation Reduction Act called the Inflation Reduction Act, if it is about climate change and healthcare?
Because that makes it easier to pass, simple as that. Inflation is a big issue. You wouldn't want to vote against an "Inflation Reduction Act", would you? Just think of the poor, the starving children, etc. A good choice of name has truly magical powers, of the sort that make people just stop thinking critically.
Being French, I will give French examples:
ALUR Law "Access to Housing and Renovated Urbanism": its most striking feature was rent-capping, which caused a vertical drop in rental construction and a long-lasting shortage. Also, officially it should have made co-location easier, by not making all tenants guarantee the financial obligations of the others. The obvious consequence is that landlords now only do co-locations when all the tenants are rich enough to be able to afford the full rent on their own, since they are no longer guaranteed by the other tenants.
Source: I'm in the business. To illustrate, I grabbed a housing starts plot from Le Moniteur and added the dates. There was a lot of ruckus in the press at the time, but all these articles are only available under subscription unfortunately. How it went should not be surprising to anyone, it is well known that price control is a reliable way to create shortages. Later, the government backtracked in panic, but the damage was done. The effect of this law was in fact about as bad as the 2008 financial crisis.

"Anti-discrimination law": makes it illegal for landlords to discriminate on anything other than revenue. So if a landlord does not pick the richest candidate, they can sue the landlord for discrimination. Many have not yet noticed, but this makes it illegal to rent to anyone else but the richest candidate. It's socialism, what can I say.
The German "Green Energy transition", and assorted legislation, whose official purpose is to be green, resulted in Germany putting their old stinky coal powerplants back online.
Examples are countless.