Nothing happens instantly because they have to actually check the reports and check the person's history, stats, and the like. If you'd take the time to actually look at the help forums, you'll see there's plenty of people getting restricted or banned from crucible. Reports aren't enough to get someone banned, they have to be investigated first, and expecting an instant result from your report is unreasonable. If a report led to an instant ban, there'd be so many trolls just reporting people for no reason other than to get them banned.