But there are plenty of jobs in tech that don't expect you to be super productive and work very long hours - it's just not the elite $250k++ plus stock options jobs where you're working on the exciting stuff. I know plenty of people in tech that do 35-40 hours / week. They can't retire on their savings after three years though.
No, the discrimination could be directed at people who refuse to work the additional overtime, or it could be the reverse; employees are given an infinite amount of work or short deadlines to complete tasks.