If you planned to visit Antarctica and your return trip got cancelled and your month long trip turned into nearly a year, then yeah I think most anyone would say you were stranded in Antarctica
Anything goes wrong, you can return at any time. You're not able to stay, there are plans that can bring you earlier, but again, you're cool with it.
The only people not cool with it are political goons and the guy who owns a ship company that would benefit wildly on a "rescue mission". Even if fabricated.
And I believe the astronauts are less stranded than researchers at McMurdo since getting out of Antartica in bad weather is harder than getting down from the station in the standby capsules.
Are they stranded? technically yes. Do they need rescue? no.