Capy Diem 🔞

Some of the characters and stories left behind imply or say that the Pale King brought about higher levels of consciousness, but I'm not entirely convinced. Even without the Pale King, most characters retain their higher intelligence. On top of that, some imply they come back and forth from beyond the kingdom, where supposedly they'd lose their intelligence. We've also seen higher intelligence emerge from Deepnest, the Hive, and even a bit at Kingdom's Edge without the Pale King. I think the most the Pale King really did was free the people from the Radiance, but is still a ruler that spread his own kind of propaganda, even if that's not how he saw it, and subjugated people.

It could be argued that the Pale King meant well, and maybe he saw freeing bugs from the control of the Radiance as a good thing. We don't know THAT much about the state of the area before he arrived because of his concerted efforts to tear down anything related to the native culture.

But it is true that he showed up, conquered, and promptly began a campaign of cultural erasure. I guess the only evidence we have that he might've been right to do so is the fact that the Radiance is directly responsible for the heinous mental/spiritual superplague that tore the kingdom apart.

The fact that Silksong shows there are other extant civilizations casts further doubt on the story of him uplifting bugs to be more than creatures of instinct.

As far as I know, rest of the existing cultures did just fine on their own before PK waltzed in. There is a possibility that all the neutral bugs were more wild and that he (alegedly) uplifted them, but that could have been enough and would have kept him as just the benevolent leader of one of the groups that joined in.

But, for whatever reason (his arrogance, void, influence of his newly uplifted people, pale lady?) he thought the rest of the existing cultures were still savage and he needs to enlighten them.
The first conflict was probably with moths and the Radiance, who was already bothered with king's presence, but now he wanted to take the moths away (and he eventually did).
Snail shamans ended up being experimented on for void/soul purposes, few that remained just staying hidden.
Mushrooms were left alone because... they are not bugs.
The mantis kept their independance due to their combat skills and prowess, even with traitor lord turning traitor.
Deepnest was too much to handle so he diplomatically offered his seed in return for subordination.
Bees stayed hidden and didn't deal with any of this, as far as I know.

We are mostly left to deal with the mess PK left behind. Pissed off radience, sealed hollow knight, insane citizens, ruined kingdom and our protagonists very existance. We may see the glory days through those that were close to him and believed he was doing the right thing, but it's practically propaganda. Most of them don't even know all the underhanded stuff he did.

Radience is too far gone and killing it is the only thing we can do to stop it. PK is dead and Radience is just lashing out in anger at this point so it needs a few tendril slaps to the face to chill.

I am certain the game is meant to impart the impression that the Pale King was a monster. As pointed out in another comment, he is very much an Ozymandias. ("Beyond lies the last and only civilization. Hallownest", and it's dead), and that is the throughline of most of the game, between the vessels, the dreamers, the closure of the kingdom and capital, the failed expansion into Deepnest, the missing palace, the desolate roads and overgrown gardens, so on. PK was a failure, and the story doesn't shy away from it ("No cost too great", he thinks to the last).

Despite what you said in another comment, the "good" ending isn't a celebration of monarchical achievement, but the opposite -- only by rejecting the King's scheme, symbolized by the Kingsoul transforming into the Voidheart, remembering his sins and uniting the Void (in a way, the last frontier of his colonialism -- an amorphous essence that he imposed both shape and identity onto) can the Radiance - herself a violent Reaction - can be defeated, the Siblings find peace and the Void return to its natural state, freeing Hallownest to become something new.

The Knight also has the option of perpetuating the kingdom, which is a failed prospect, one Hornet steers them again. Accepting the king's bargain to save the present for the second time is merely dooming the future. The Hollow Knight's sacrifice is rendered meaningless, as is the Knight's.

More materially, every tribe he came in contact with chafed against him: the deal with the Mantises, the begrudging acceptance of his rule by the Shrooms, the entire Deepnest situation, the Hive maintaining independence, the Mosslings agreeing only to the construction of the Pilgrim's Way. The "Light of civilization" was resisted at every turn by everyone not directly under his rule, and few are worse off as a result. The Mantises in particular maintained their way of life, even faced with the catastrophe of the Infection. Only the traitors, who desired power, succumbed to it. (and why would you want power if not to lord it over others?)

Lastly, his kingdom was rife with class antagonisms: the exploitation of the maggots, the divisions within the capital, the mass killings in Soul Sanctum, Xero's assassination attempt on the king. Hallownest is not, in my opinion, portrayed in a good light -- it is an aristocratic, oppressive and colonialist state that ages ago collapsed under its own weight and its God-King's negligence and preconceived notions. He is a liar, a fraud, an autocrat and oathbreaker who doomed his people and many others. The game, textually, symbolically, and mechanically via the Voidheart, rejects his prepositions and accepts a different future.

as elaborated in more detail in the other comments, it's entirely possible to read hollow knight as a wholly anticolonialist narrative, keeping in mind how many things are propaganda in-universe. feralphoenix on tumblr has a lot of good analysis on that particular perspective