Deadlines exist because software doesn't exist in a vacuum, but other people depend on it being delivered. Whether so it can be sold to make money before someone goes out of business or a partnership fails, or its features arrive on time as promised for the start of the school year which can't be moved, or as the foundation for another project that has its own equally valid deadline later on.
Deadlines exist because people need to make plans and be able to rely on them, which is how our entire society and economy function.
People work overtime in every industry to meet deadlines, it's not just engineers. The only question is whether or it's good for you financially.
Whenever you take a job, it's up to you to do your due diligence in talking to other employees to find out what the working hours and flexibility are like in practice, and judge that against the salary, and decide if it makes sense for you.
Fortunately, there is huge variation in both salaries and expectations of hours per week, and the best thing you can do about places that pay little and work you long is to not take their job offer, or leave. Then supply and demand can do its thing and they'll be forced to adjust or go out of business.