I hope I'm not opening a can of worms here, but... well I was raised Catholic (therefore Christian) and I NEVER heard anything anti-gaming in my life. Not sure if it means Catholic is more liberal than the other Christian groups, or if it’s simply a thing that somehow managed to piggy-back on top of religious movements in some regions.
In fact... other than some religious groups bashing some very specific games, this is the first I hear of Christianity as a whole being perceived as anti-gaming (maybe I missunderstood your message?)
There is a misperception of Christianity in the more agnostic and atheistic sectors of our society that assumes the religion is restrictive to the point of self-righteous anal-retentiveness. While there are examples of such people proclaiming the christian faith, they are not nearly as pervasive as those outside it tend to believe. I'm not sure why there is this desire to assume Christianity is a hateful, narrow-minded faith that denies one any ability to have fun or participate in the real world without looking like you're squelching through the most disgusting mire you can imagine, but there is, and it pervades popular culture.
Thus, people react with shock and amazement if a Christian illustrates "open-mindedness" to the point that they can do things that "normal" people do.
Usually, no harm nor offense is meant. It's just how their expectations diverge from reality. Add in that many Christians don't bother to profess their faith unless it comes up in an important way, because to them it's as normal as having a job, and people just don't realize
that the normal dude they've been hanging out with is a Christian. After all, he's not trying to burn witches or scourge homosexuals through the streets or talking about how pop music is Satan's work, and that's the unfortunate and unfair stereotype (that even most people who knee-jerk to picturing it will generally agree is unfair when they stop to think about it).