Doesn't have anything to do with Arsenal, I'm questioning it as someone who lives in Germany. Their support was local until their recent resurgence when most 'fans' came out the woodwork, when the club was lounging in midtable nobody cared about them. Second biggest revenue generators doesn't mean shit in a one-horse race, had a quick look and they weren't even in the top 20 for revenue for all but two or three seasons in the last 15 years.
I'm actually not saying that they are a small club, maybe it's just semantics but I associate 'giants' with clubs like Real, Barca, United, Juventus or even Milan despite their fall from grace. Also the Dortmund fans around here are as arrogant as Bayern pricks and smug as shit and I still remember that Guardian article there was a running gag in the Dortmund dressing room about being linked with Arsenal as if they were a bigger club. Basically, fuck the lot of them.