This is a tricky one. On one hand, I don't think you should have to go through the proper channels to get samples. Chuck D's said before that there's no way someone could make an album like It Takes A Nation Of Millions... these days since you just wouldn't get the permission for all the samples, or if you did the fees would be so high it would make the release untenable. The only way to go about it would be to do it without permission. A band like Daft Punk is in a very different position to one like Crystal Castles as well, they have a lot of money and resources backing them. They can just send out some lawyers to go and get permission for any samples. Crystal Castles also seem to incorporate the appropriation of images and sounds for their own ends thoroughly into their practice, like their logo being the Chanel logo.
However, this isn't the same as a hip-hop artist sampling a Motown record they know they'll have to pay through the teeth for, or a punk band using film samples without permission. The track was available to be remixed, but only if Lo-bat was credited as the source, it wasn't released commercially and these same conditions were applied to the new track. They didn't need to be underhand to make new music from a track by Lo-bat.
I suppose it's possible that they didn't know this. Maybe they thought it was copyrighted and they didn't want the massive hassle of getting permission, or perhaps they make a silly mistake and misunderstood the terms of a creative commons license. There's also the fact that this was an unreleased demo. They did put it up on myspace, which constitutes a release, but they might not have thought about that. People regularly throw up new music onto their myspace profiles as soon as it's completed, they could have just been a little too eager and the thought "if we're putting that track up we need to mentioned it's CC and from Lo-bat" might not have occurred to them.
Basically, they seem to be getting a little too easily condemned. This could have been an oversight/cock-up rather than maliciousness.