Yeah and that's fine, you probably get enough candidates willing to grind through it anyway if you're at The Big 4. Interviewing is a two-way street though so obviously I am going to have it color my decision process. I want to know what challenges actually happen on the job and if I can solve those challenges, and if you ask me to code up a shortest path algorithm on a whiteboard but that never appears on the job, then it seems like a pointless test to me.
Compare this to other companies, both large and small who have asked more reasonable challenges such as; "set up MySQL master/slave replication," "write a script that parses a text file in Python," "build a 2-tier architecture through terraform," "troubleshoot these issues on a broken server." Obviously these aren't as fancy as "implement an algorithm on a whiteboard," but it shows me as a candidate/potential candidate what type of problems to expect on the job. As a DevOps person I don't believe in whiteboarding for interviews, nor do I believe it should be a thing for devs, but if a company prefers to interview with this method like Facebook and Google (have received study material for both), I'll continue to focus on the companies who are practical about interviewing instead as it's worked out fine so far for my career path.