Ooooh, buddy. You have no one to blame but yourself for this can of worms.
Skeptical is 100% just as correct to use as sceptical. As a matter of fact, wouldn't you know it, even my auto-correct wants me to use skeptical. If you google "sceptical" what pops up first? Skeptical. With a tiny little footnote showing that it could also be spelled sceptical. OH, and that's through Google UK. Which just happens to be the *only* country that sceptical is even close to having a majority use in. At a 50/50 split.
The spelling of skeptic is, historically, more accurate than sceptic regardless of your personal opinion, because it actually isn't derived from sceptique. That's a huge misconception. Sceptic is derived from from the French word sceptique. Skeptic is derived from the Latin word skepsis. Latin is, by far, the older language, which many other languages are derived from. Including French. The evidence, as you say, is in the etymology. You did, you know, research the etymology, right?
Hate to break it to you, but it's not just the United States that uses skeptic. A solid majority of worldwide English speakers use skeptic. There is not a single country, in the whole world, that uses sceptic more than skeptic. Not a single one. So, when you say "obscure regional dialect specific to only one place on earth, such as America", I don't know what the crap you're talking about.
I did my research. And here are some numbers for you.
US - 92% skeptical
UK- 50/50
India - 68% skeptical
Philippines - 92% skeptical
Canada - 83% skeptical
Australia - 56% skeptical
Ireland 51% skeptical.
New Zealand 61% skeptical
Jamaica 72% skeptical
Trinidad 59% skeptical