I mean, there are tons of backgrounds you don't see in team photos every day. There are only a few that cause any substantial reaction.
I agree with Meaty in that the real travesty is serving up bad football and bad results, despite assembling a team full of hand-picked players. If the problem is that they aren't looking at players from different backgrounds due to some kind of explicit or implicit policy, they should be apologizing and ammending those policies immediately. Otherwise, best to focus on getting a better squad assembled led by the right coaching staff to win some fucking football matches.
If academies are the problem, then Arsenal should sort their own issues out and use the FA and other interclub orgs to ensure that others do the same.
Whimpering apologies driven by PR that pander to internet outragists are stupid, pointless, and feckless at best, while being divisive, racist, and insulting at worst.