I have no idea why anyone would want to pirate an alpha version, but I don't see how they could miss the 'THIS IS AN UNFINISHED ALPHA' messages plastered everywhere or the numerous disabled features, so I find it unlikely that anyone would mistake it for the full version. I doubt Larian are losing much sleep over this, to be honest.
The morality of it is an interesting question - after all, unlike a release version, there's no way anyone is even theoretically losing money from this. My main concern would be that the pirates, who obviously didn't back the Kickstarter, will misunderstand what Larian is trying to do and start complaining about the isometric view and turn-based combat. But let's face it, that will probably happen with the final game as well.
