The selection listing states that the rack...
The selection listing states that the rack is for 1.25" hitch receivers - is this version compatible with 2" receivers as well?
Yes,, if you buy a 2" to 1.25" (D-170) hitch adapter. They are priced at around $40 and you can find them online or order one at your local auto parts store.
You can technically add the adapter and it will work fine. However, I highly recommend getting the rack that is the correct size for the hitch on your vehicle. Having fewer connections makes the rack more stable. Using an adapter is fine to add flexibility, but buy the size rack that matches the hitch of your primary vehicle and adjust from there if needed.
There are more Thule T2 2" racks on the way and they should be back in stock within the next day or 2. If you have a 2" hitch, you will be best off getting the 2" version of the T2.