No idea why you're fishing for an answer when you know what it is People bot, it's nothing new, it's been discussed to death. We all know it's lame and shouldn't happen, the people that do it and actually think they're competing are delusional and should move on to a new game.
You can make it to the higher ranks easily without bots, it's just CLEARLY an advantage for farming mats/keys Over the course of the season they become less and less effective as the only important thing separating people on the leaderboard is skill and paragon levels.
All in all, they're lame af and players using them should be banned across the board, as they would breaking any other ToS. Sadly Blizzard won't take action as they're desperate to get more players online, which is fair enough as the game is only just becoming popular again