You can hold both opinions - that City are cheats and Arsenal are the master of the dark arts/time wasting and general shithousery. It's not one or the other, and there's no need for you to go on this massive whataboutism rant.
Conceding an equaliser in time add-on kinda proves they are not masters of the dark arts.
They're dabbling in the dark arts but there is a long way to go before they're masters.
They are Draco Malfoy, not Voldemort.