It's not all magi who are like this. But the PCs are.
Also, the Gift makes everyone (including grogs) in setting think that magi are like this (or something similarly obnoxious), even if they aren't.
Certainly not the only person who doesn't make that assumption.
My first mage was an initially insecure Bonisagus magus who was gradually revolutionizing how magi work together; he was very concerned with how magi treat each other and mundanes.
My second was a Tremere who was determined to be a good soldier and was on his way to being an effective House hatchet man. He didn't care about mundanes particularly, but he wasn't a sociopath.
My current hasn't settled yet, a Magus Mercere, but I think he's out to transmutate Mythic Europe through trade and mass media (ballads and plays). A visionary who sees a world gently guided by the invisible hand of the market and media. We'll see how that goes.
Other magi from other players included a tribal shaman, an actual Tytalan sociopath, a Flambeau Irish revolutionary, a comedic avaricious Tremere merchant, and a very shy and retiring Ex Miscellanea Herbam maga.
Power corrupts...
As has been mentioned grogs might tend to see magi this way despite their best intentions. Most of my Tutalusagi want all people to be the best version of themselves, but that doesn't mean they make life easier for them.
I think it makes sense that a non-trivial portion of the OoH's magi have skewed perspectives on the outside world and tend to be anti-social (not sociopathic). Covenants are often enclaves of esoterically-educated Latin-speaking oddballs who need to spend enormous amounts of time in their labs, with each other, or traveling to/from other covenants/weird locations/tribunals. When trouble comes knocking, they are mechanically inclined to cajole each other into being "the one to go" with the companions on any given adventure. When mundane conflicts rage around them, many individuals (or covenants as a whole) go out of their way to avoid becoming involved. The duke of whatever will be dead in another 40 years while the magi will be a third of the way into their breakthroughs -- they don't want quaesitores breathing down their necks, so why bother? If the magi venture out of the covenant into Dominion areas, they encounter people speaking local languages (which they may not speak) who inherently distrust the magi and typically have no respect for them in spite of their power. Especially with older, more secluded magi (or ones with Blatant Gift), they may be so insulated from mundane (non-covenant) life that their rare interactions are extra awkward.
Even so, there are probably plenty of exceptions. Some of the gilds in the Rhine promote more interaction with mundanes, magi with Gentle Gift aren't inherently distrusted and can use that to their advantage, and characters like Redcaps (not magi, but heavily Hermetic in culture) would probably get along with/understand mundanes just fine.
Considering that a lot of magi will spent 95% of their time confined in their lab, with for only interaction their familiar, and on some occasion an apprentice, I believe the right term to describe a magus is not necessary anti-social, but "socially challenged", mostly for lack of practice (to differentiate from the real mental case).
Since most of their social experience is with peers (suffering from the same problems), each magus has probably a purely theoretical understanding on how to behave in mundane society (thanks possibly to some Summae on Etiquette 
). So when confronted to reality, they might have some issues adjusting...
Most magus are smart, very smart, so I am sure that if they see the need or the interest to work on their social skills, they will get some success, but as I said earlier, why waste time on such petty details when you have to deal with Faeries, dragons, djinni and very interesting labwork.
For a magus, the world is at least four times richer and more complex (considering their understanding of the four Realms) than the one of the next guildmaster/bishop/ruler, so why focus on the tiny mundane bit - where you know you are struggling because of the Gift - when you can delegate this task, so you can keep focusing on the really challenging one: negotiating with faerie Queen (or other powerful supernatural being of your choice).
That's a good distinction. To clarify my intent, I meant exhibiting anti-social behavior, not that magi have Antisocial Personality Disorder.
In order to mask the presence of the Gift, you need to give someone universal magic resistance. The only known way to do that is through the Parma.
I suppose that a PeVi spell of sufficient potency(at least 30 for Touch/Sun/Ind, so that we get warping as well) could shut down the Gift, but there's currently no effect seed for it, so that would have to be discovered first.
(And good luck with that - are you throwing experimental Perdo Vim at your Gift, or someone else's? The Quesitores would really like to know.)
And even if you had such a spell, I'd only allow it to negate 3 points of Gifted Penalty, so someone with Blatant Gift still has issues.
-Albert