Everything from the hiring company's perspective also applies to the candidate.
The company is investing a lot of time and effort in the interviewing process. The candidate has been preparing for weeks for an assessment that has nothing to do with their actual job, and is being assigned multiple take-home challenges that take 4-8 hours of their time, etc.
The company wants to feel free to shop around and spend as much time as they want to hire "the right candidate?" The candidate is entitled to the same, shopping around for "the right company."
The company wants to avoid a bidding war to get the candidate for the least amount of money they can get away with? The candidate wants a bidding war so they can get the most amount of money they can get away with.
The company asks the candidate what salary they are expecting. The candidate can simply ask what the range for the position is, since the company has that information.
The company spends the entire interview assessing the candidate, and maybe asks if they have any questions at the last minute? The candidate is entitled to know just as much about what they are potentially getting themselves into by accepting an offer as the company is by hiring a candidate.
etc.
The process is a 2-way negotiation between equal parties.