The Belgium international was already on a yellow card when he kicked the ball away after conceding a free kick, thus incurring a second booking for delaying the restart at the end of the first half.
Trossard's red card came just a few weeks after Declan Rice's dismissal against Brighton & Hove Albion for the exact same reason, and both Arteta and his coaching staff were evidently bemused at the decision.
Before Rice was sent off against Brighton for kicking the ball away, Joao Pedro memorably booted the ball halfway up the field after Arsenal won a throw-in, but the Brazilian escaped a booking, which PGMOL chief Howard Webb admitted was the wrong decision.
Deja vu struck for Arsenal at the Etihad, albeit not quite to the same degree, as after the Gunners won a free kick, Jeremy Doku tapped the ball back into the Arsenal half, although referee Michael Oliver did appear to be pointing for the free kick to be taken where the Belgian kicked the ball.
Arteta makes "very clear" admission after Trossard red
However, the game did not restart from the position where Doku kicked the ball, and speaking to Sky Sports News after the game, Arteta suggested that the Belgian's 'delay' should have been punished instead of Trossard's transgression.
"I think it's very clear. Very obvious, hopefully what 100 per cent of what people thinks. It's the second time it has happened in five games. It's really, really worrying if we want to see the best of the Premier League," Arteta said.
"Anyone has played football [can see] it's less than a second. Less than a second. The previous one [Doku] is more than a second. That's it, simple.
"It's impossible [to play after that]. It's very hard already against 11 players, impossible. Because we are put under pressure to defend with six in our box time and time and time again. That's it.
"It's not my job to come here and judge what happened. My job is to survive in the most difficult environment in football for 55 minutes. To get things done to survive. That's my job, the rest is not my job."
Arteta hails Arsenal "miracle" after Trossard red
Prior to Trossard's dismissal, Arsenal replied to Erling Haaland's 100th Man City goal through a Riccardo Calafiori stunner - on his maiden Premier League start - and Gabriel Magalhaes's header from a Bukayo Saka corner, the same combination from last weekend's North London derby victory.
With 10 men operating in a low block, Arsenal put in a magnificent defensive shift in the second half, only to have their hearts broken by a 98th-minute John Stones leveller, City's latest equalising goal on record in the Premier League.
Despite the gut-wrenching manner in which Arsenal dropped two points, Arteta was unsurprisingly beaming with pride at his side's "miracle", telling BBC Match of the Day: "I am so proud of the team.
"We played the game in a difficult context. Playing against the best team in the world. Obviously, it is already a miracle we played 56 minutes at the Etihad with 10 men. It is unbelievable what we have done."
Arsenal are next in action against Bolton Wanderers in the EFL Cup on Wednesday night, the match that Trossard is suspended for, before hosting Leicester City in the Premier League on September 28.