I suspect it functions this way because this is how most webcomics outside of tapastic work -- the "main page" of most websites is going to be the most recent update. There are a few exceptions, but most of the time webcomics readers expect that, when clicking a new comic, you'll see the latest page.
and I agree with @Ringarune that a looooot of artists would want the first impression of their work to be "here's what the comic consistently looks like right now" rather than "here's the first page I ever drew."
I do think it'd be neat if that were something you could toggle yourself, as a creator -- where you want the "landing page" to be for someone who's never seen your comic before -- but (a) that could get confusing for readers wondering "WHY IS IT DIFFERENT FOR EVERY COMIC" and (b) of all the changes I'd like tapastic to implement, that one's pretty low on the priority list.
There's an easy fix for this if you're copy-pasting a link to someone! If I click on my comic, the URL is:
and if you click that, you'll land on the most recent page, or whatever page you were on last. But if I then click on the first episode in my episode list, I get a URL that looks like:
and that's a link directly to my first episode. : ) So I can send THAT link to people, and it'll direct them to my first page!
