I like that we anthropomorphize Pluto--humans seem to be built sociably, evidenced by our readiness to treat objects as people. And, I hasten to point out, humans do not always treat people well.
So people's indignation at the "disrespect" for Pluto does show a subconscious worry that now that Pluto's in a different category, it will be treated differently.
Which is, frankly, kind of ridiculous. Like, what the fuck are humans gonna DO to Pluto? invalidate it? Stuff it in a locker? Deny it healthcare? Make it illegal for it to open a bank account? Bomb it? (Okay, we could totally bomb it, but WHY.)*
But Pluto's defenders don't really think it through; they just perceive it's in a "lesser" category now (even my fellow Space Placers refer to its reclassification as a "demotion"), and that's as far as they go because they know that humans treat different categories differently.
I've had kids ask if Pluto blew up. It kind of makes sense if they hear adults complaining about how Pluto's "not a planet anymore." Last night a family member asked if it's still included in the solar system if it's not a planet.**
But Pluto's the same thing it's always been; and we've just changed how we're talking about it!
I think the reclassification reflects our expanding knowledge--we've discovered a bunch of things like Pluto and unlike the things we call planets, so this is a whole new category! And we're willing to change it! But our change in its categorization, people perceive, is a change in social status.
People who argue about there being "natural categories" or "scientific reality" seem to ignore the point that it's all humans interpreting it, with our dumb little caveman brains that are still trying to work out if this reality is going to kill us or not.
"It's a FACT" okay, what are you gonna do with that fact, bruh.
*Though astronomers did joke that it's a good thing the New Horizons mission was already underway because it would have been a lot harder to sell a Kuiper belt object than "It's the only planet we haven't visited." Which just goes to show the recategorization changes how we interact with it!
**Answer: Yes, it's just in a different category of Solar System Objects!