Clark & Washingtion LLC interview questions

A few days after applying for the job I was contacted via phone to schedule an interview. After the interview, I was contacted in the following 2 weeks and they expressed their interest in extending a job offer if I was able to start working in the next 3 days. It felt unprofessional to condition extending an offer they way they did and to expect one to drop everything and start working in 3 days, especially when during the interview they knew that my employment finished by the end of the month, basically 2 weeks after their desired starting date.