There was a common purpose between Arsenal and City fans for a number of years, most discernibly from 1996 to 2008, for reasons which I don't need to expand upon, which made the bile which was directed towards us from many Arsenal fans, following the takeover, particularly hard to take. I would say that Arsenal fans took our change in fortune as badly as any set of supporters, even united's - possibly because at the time, buoyed by so many years of almost unbridled success, and all too aware of City's previous hard-wiring to self-destruct, their supporters were cocooned from any sense of threat to their clubs enduring hegemony.
What especially stuck in the craw was the widespread suggestion from many of your supporters that we did not deserve this because our club somehow lacked "history" and this served to annoy for two reasons:
Firstly, because it shows a complete lack of understanding and respect for what was (and is) a leading English footballing institution. It may not have won as many trophies as Arsenal in recent years, but City's narrative, the real history of any football club, is as interesting as any other cub in the land. Anyone who fails to appreciate the currency of this doesn't really 'get' what it is to be a football supporter.
Secondly, because it was espoused by Arsenal fans who were ignorant, or willfully blind, to their own club's dubious past: buying their way into the First Division at the expense of Spurs; the highly questionable business practices of Henry Norris; George Graham's bungs; the Danny Fizman cash injection (aka: investment) in the 1990's; the naked self-greed of the club's central role at the vanguard of forming the TV deals in the late 80's and early 90's at others club's expense; as well as their wholly selfish membership of the G-14, are all examples which many of your supporters conspicuously avoid reconciling when talking about "earning" the right to sit at the top table. Possibly because they aren't aware of them. People pontificating about "history" really should do a bit more research on their chosen subject.
That is why you see so much vitriol directed towards so many of your supporters from City fans both on here and more generally.
No-one likes a hypocrite, especially one that turns on you when you have a bit of good fortune in life.
It does seem, after all, that you can buy class. Perhaps you should take that banner down, just like united did once we'd rammed it down their throats. That would show a bit of "class" hitherto all too sadly lacking from many people connected with your club.