That is odd. But probably is region based - I still see BBC on that site, but I'm in Europe.
And you're right, no subtitles. If you want to watch a channel, you need to understand the spoken language. For BBC subs are not necessary, their shows are crystal clear (except maybe the current Doctor Who companion - she talks a bit too fast). For ABC however, sometimes it's a bit hard to follow.
Now I see only ABC 1 Australia here and searched desperately for a possibility to see ABC Three stream because of a certain TV show. It's not available anywhere probably because of my region.
Luckily, the show was bought by a local network so I can still enjoy it, although later than I wanted. Will write about it in series thread, just not yet, too early to say if it's crap, mediocre, very good or finally an aussie masterpiece.