Around 81 million monthly players at the end of 2017. (You'll have to google this - the best source I can find is an account selling site, of all things)
Let's say that every single one of those players only played a single game all month. Thats 8,100,000 individual games (10 players per game - keep in mind, the real number is probably a lot higher)
Let's make an extremely conservative estimate that 1% of those games generated a single report. Flaming, inting, whatever.
That's 81,000 reports that have to be adjudicated. Let's split it and say that 80% of these reports are for flame, and 20% of these reports are for int. That's 65k flame, 16k int.
The flame reports are easy - someone just has to read the chat history. Let's say it takes someone about a minute to clear a single report (reading the chat and clicking punish or not punish, kinda like the old tribunal)
Int reports are a lot harder; someone needs to actually watch the replay of the game to make a decision on that. Just looking at KDA and build isn't enough, you have to actually watch how someone plays. Let's say these take about 10 minutes each.
With these numbers, each month, Riot staff would be spending, *at minimum* 1,350 hours handling flame reports, and 2,667 hours handling int reports. 4,017 hours each month, 48,204 hours per year. That's **25.11 MAN YEARS (40 hours/week, 1920/hours year)**, spent doing nothing but report handling!
(And what a shitty job that would be - imagine exposing yourself to the worst the player base has to offer, all day, every day.)
This doesn't scale.
Back in the old Tribunal days, the system was backlogged up to six months. This means people were receiving punishments for something they did _long _ after the incident had passed out of the memory of everyone concerned. This is completely worthless, both from a justice, and a reform standpoint, something Riot is on record as being large proponents of.
Some kind of automation is absolutely necessary to keep up.
The accuracy of the report system as it comes to flaming chat appears to be quite high - keep in mind, those of you demanding that a human handle your cases, that a human would be punishing you in the same way that the IFS would be. The rules didn't change.
If you want to play around with these numbers yourself, [here's a google spreadsheet](https://docs.google.com/spreadsheets/d/1zHr5Is-kblYo1vput3VSG6Ly7KVC4WA5qAo1iabJOI4/edit?usp=sharing) so you don't have to redo all the calculations.