Are you confused with this idea that people can be assholes, and in a moment of frustration would do something bad in the hopes of screwing over someone else?
yes, valve has had constant problems in dota2 with abusive reports leading to bans. Streamers that stream all their gameplay that have never even once done or said anything abusive got bans.
Because people are assholes. They'll blame that person for them losing a couple points on their rating, and report them as a form of revenge.