Considering your handle and avatar, it makes sense.
It absolutely strains credibility. I was going to type out my recollection of events, but I tired of it, so here's a CNN piece that covers it:
Bottom line: the amount of contacts between Team Trump and the Russians is simply too large to ignore. Couple that with the ousters of Manafort and Flynn, the recusal of Sessions (and potential ouster; I've read that Trump was not happy with him for recusing himself), the investigations that appear to be underway by the IC and congressional committees, and Trump's staunch refusal to say anything negative about Putin/Russia or release his tax returns, something smells damn fishy.
Also, as far as I'm aware, Wikileaks has been utterly silent since the election.
I'm sure that's part of it. It's pretty clear where his weakness is (ego) and they know they cannot expect straight, honest answers out of him, so they'll keep hammering this until they get some answers. (Trump also did himself no favors by demonizing the media and intelligence agencies.)
Just look at his tweet storm from this morning. The Russia story is clearly bothering him and he's lashing out. And in doing so, might have just lent more credence to investigating him. As ED said in the 100 Days thread, if there was a FISA warrant to tap phones at Trump Tower, there was a damn good reason for it (getting that warrant is not in any way easy....especially for something as high-profile of a US presidential election).
But to your larger point, I don't see this being looked at as a game by the vast majority of those in Washington. This isn't a ploy to smear Trump (I don't think Tom Clancy could have come up with this one); there are absolutely legitimate concerns here that demand thorough investigation. And there are more and more every single day it.