Given how much time an interview process usually takes, I don't think 45 minutes is a lot to ask; if I were the interviewer or were setting policy, I'd advocate for, "sorry you feel that way, but we won't be able to continue the interview in that case".

Then again, not completely sure what the GP means about "screening stage"; if a take-home assignment is given before any kind of substantive interaction between the company and me, that'd be a definite red flag. I'm not going to spend 45 minutes doing your resume screening for you.

I guess it was misleading when I said "that's fine". For certain roles it's required, so if a candidate refuses, we pass... It just signals that we're not a great fit for each other. We treat this as a technical screener. We get a lot of applicants for these roles and we need to quickly eliminate candidates that are not technical enough.