The reports attach the name, server, chat channel, chat logs, game position, game logs, etc to the report depending on the type of report. That enables the GM to do a review of the relevant data. I think chat reports also bring in the rest of the convo, not only the person reported so sometimes, more than one person can get actioned.
This is like false 911 calls. If someone genuinely thinks something is bad, Blizz leaves them alone. If they (or a group) are intentionally trying to use the system to abuse players, that is against the rules. I don’t know how well that is enforced though.
Yeah the current system tends to be less than optimal and sometimes requires multiple tickets for complicated issues. The other problem is that people put in tickets for things CS does not help with so when they finally get a reply it is something they don’t want to hear. Like, “we can’t give game hints so please try a third party site like Wowhead”.
They put together a CS forum article on it a few years ago that is helpful to learn what CS can and can’t help with.