I thought those days were over, but guess not. I should have read, now I wasted a hard pull.
Per TC:
This offer is available only to applicants who are permanent residents of the United States, with the exception of Puerto Rico.
Two years ago Discover had same rules, but they turned around and realized how much business I would bring them. Apparently Barclays's not there yet. When permanent residency is required, usually issuers will ask the question in the application itself with a note indicating it's only for permanent residents or citizens, instead of "tricking" you into submitting application. Evil.
This corresponds with people asked to have their green card/passport copies sent for verification.