I can see why some are weirded out, after all, Hide is smiling in a very dire situation. We know that Hide always smiles for Kaneki, so he can help him relax and open up. But also, there is actually a parallel between Hide and another character that does the exact same thing:
Both of them laugh in an intense situation in an attempt to ease the mood and make the ones they care about feel a bit more at ease. If they show they don’t feel stressed (although they probably are on the inside) it becomes easier for others to open up and feel better.