That's true, though real world performance is often more like 350kbps. The Iridium NeXT series satellites and second generation network are a fairly recent thing to go into production use in the past couple of years, before that, an individual iridium terminal was limited to about 2400 bps with v42bis compression. There were some famously weird multilink PPP bonding solutions used in Antarctica with four separate Iridium modems and antennas.
Aside from the fact that Starlink connections are or two orders of magnitude better in throughput and latency, the biggest problem with Iridium is the cost. It's just simply out of the realm of affordability just for the likes of streaming some videos or playing games in their off-time.
Now that I think about it though, the Starlink user terminals likely won't be able to survive the harsh winters at the poles. -30 deg C and low tolerance for high winds means this would be tough unless some type of non-obstructive sheltering could be provided.
I imagine that compared to the fully-loaded cost per hour of Amundsen-Scott station just to exist, be periodically resupplied, pay salaries of staff, buy equipment, transport logistics...
Even if you maintained multiple $1.25 per minute (or $5 per megabyte) Iridium links, operating 24x7x365, it would be a teensy tiny drop in the bucket compared to the total budget of the station.