This bad behaviour may include ignoring the Robots.txt file standards that tell BOTS which pages they can and cannot access and over crawling a site to the point of bringing it down.
However the main reason why a BOT would be labelled a Job Rapist is that it steals jobs without the site owners consent. Instead of asking if they can take job adverts from Site A to put on their own site they instead crawl the site without permission stealing the job content AKA Job Raping.
Job Rapists are mainly aggregators who are trying to build up their database of jobs without paying for them.
If an internet police did exist then the job raping of recruitment sites would be a severe crime alongside email harvesting, spamming and hacking.