Arvato interview questions

The position was as JavaScript specialist but I was asked for a position because they acquired a software I was previously working on so they need somebody to support it. The interview was fine but very general and they didn't asked a lot of technical questions but then I had a second interview with the team in Germany. The second interview was a little bit more technical and but they still asked general questions which were probably not enough to know if somebody was ready for the position, but they had the fact that I was already working in the software they wanted me to maintain.

I applied online and was contacted by the recruiter to discuss my application. Thereafter an interview was scheduled. After about 2-3 weeks they got back to me saying they were impressed with me but couldn't hire me because I had a Stamp 1G visa, the visa allows me to work in Ireland for 40hrs a week. They said because the role will require me to work more than that a week for busy period. What was troubling is that they already knew about my visa status before before the interview, so I didn't understand why we had to waste each others time.