They didn’t just add Summoned Skull to Archfiends. Every card that included “Demon” in its Japanese name is an Archfiend (=Demon) now. Stupid English translators I hate you so much...
How the hell were they supposed to know a random name fragment would become relevant a year later? The only one I can't forgive them on is A Deal with Dark Ruler, even though the fact it's an Archfiend card hardly mattered until Heiress.
Translating every single card name literally wouldn't work, especially factoring in every Japanese word needing a unique English equivalent that doesn't overlap.
It’s not about being relevant or becoming a whole archetype later. They did it because they didn’t want anything religious in a “kids” TCG. Examples are, among others, Demon=Archfiend, Darklord=Fallen Angel. Or many cards with religious symbols were censored.
What’s so hard about keeping the original name if it works in English (like Demon)?
You understand the reason ("religious") yet you still ask "what's so hard about keeping Summoned Skull's original name"?
I mean if it was something like changing "King of Wishes, Hope" into "Utopia" then yes, you can complain, but this is the one thing with an obvious reason for its censoring.
If something is obvious it suddenly becomes acceptable? The fact it's meant to not reference to religious themes doesn't change one single bit about how messed up and wrong it is to censor the name of a simple monster based on the beliefs of a religion.
Realistically, even if they weren't going out of their way to censor Daemon, the odds are pretty good that Summoned Skull would've gotten a name change anyway.
I think the main thing to take away here is that Daemon was a terrible archetype name. They overused it on random cards (look at stuff like Shadow Tamer, A Deal with Dark Ruler, etc.). It and Guardian should have never been archetypes.