I wouldn't say plague has a bad rep for dom behavior in general so much as there was a spurt of unfortunate attitude from a subset of users on display for the impromptu Plague v. Water fight.

overall, the stereotypes I've got look something like (going in fest order):

• light: by and large people who feel strongly about #aesthetic, which also goes hand in hand with attracting wealthier users (since buddy these UMAs aren't gonna pay for themselves) and thus strong exalters. if they were a zodiac sign they'd be leo—glamor-loving but generous; or the (eastern zodiac) snake—elegant and socially savvy.
  
• lightning: one of the flights that is most likely to attract people who match the in-universe FR lore; the stormcatcher is kind of a love him or hate him sort of deity, it seems. thus: people in microsoft excel fandom, portal fandom, or both. dom is a chance to [naruto fistclench] test their abilities. if they were a zodiac sign, they'd be the rat.
  
• fire: the few, the proud, the... uh. suffering. you gotta REALLY love fire flight's aesthetic to be in this flight, as its hot mess (no pun intended) of a dom situation is infamous. this speaks to a certain kind of strong devotion in its members.
  
• arcane: a vast galaxy (see what I did there) largely made up of the kind of people who love to self-describe as "nerdy"; often kind of cringe but in a deeply earnest way that's very cute. don't have a competitive bone in their bodies, bless them. if they were a zodiac sign, they'd be pisces.
  
• plague: hardcore types who "aren't like other girls," though most of them are too genuinely cool to do something as uncool as actually say they think of themselves that way out loud. they may not all love gross stuff, but they have an appreciation for the macabre, and probably enjoy a good villain protagonist. strong dom flight because, for better or worse, they like the ability to flex. if they were a zodiac sign, they'd be aries.
  
• earth: the flight that has changed most dramatically over the years, from a small and humble corner of close-knit folks to THE dom powerhouse and thus go-to home for users who consider that to be the most important element of a flight. similar to light's expensive tastes, this does tend to correlate with a high proportion of users who care about #aesthetic, especially with how fashionable earth-toned dragons have become lately. if they were a zodiac sign, they'd either be (eastern zodiac again) the dragon.
  
• ice: the OTHER flight that has changed a ton over the years: from being the original home for users who valued aesthetic above all else AND the original dom powerhouse, to a more chill (heh) flight of folks who still enjoy pretty things and dom culture, but don't need to be #1 all the time.
  
• shadow: another large and sprawling flight, this time largely made up of the kind of people who would have enjoyed "come to the dark side, we have cookies" memes in 2010, for lack of a better way of putting it. not the most organized or ambitious flight, but very fun. they wish they were scorpios, but they're actually more like the eastern monkey or pig.
  
• wind: fun-loving creatives; overall the most artistic flight. this sort of thing helps them fund dom ambitions despite their large size, but they're still not especially dom-focused overall. if they were a zodiac sign, they'd be gemini or sagittarius.
  
• water: probably the flight most likely to counter your expectations; rather than being a bunch of hippie-dippie dreamers to match the in-universe "oracle" lore, water flight folks are friendly, ambitious, and energetic, combining earth's (and plague's) interest in dom with a more "just here to have fun (and kick ass)" vibe. also a small flight, thus close-knit; even if the personality type doesn't match the lore, the flight nevertheless attracts people who value the aesthetics and lore over having trendy eye colors. their zodiac sign would be aquarius—clever and creative but unsentimental.
  
• nature: 90% mom friends by volume. nature folks love a good community project, and the people here are indeed pretty much universally nature-lovers. if they were a zodiac sign, they'd be taurus—a bit set in their ways, but typically cozy caretaker-types—or the dog.