Sure it's a perfectly acceptable location.

If I there's a square and I'm told to draw a line on it...I would put it right down the middle.

well, sure, maybe. but if someone handed you some slabs of quartz and said make a square that is this x this, you'd probably cut one slab the right length, cut the other the right length, and then trim one of them to be the right width, not trim both. so, its all how you look at the project.

fair point!

i'm sorry you were disappointed by it not being what you expected, its so infuriating when these situations present themselves. i remember how i felt when i saw all my kitchen cabinets had been installed 3" too far to the right.... GAHHHHHH!

but either way its a seam... i'm not sure centered is more magical than not, once you know where its going to be.

Sometimes the seam will go off center in order to save material or to eliminate the need to purchase another slab if that's the case you need to look at the budgeting in the contract. If the contractor had enough material to center the seam he should have. In any case I wouldn't have it redone.

How come no one asked the dimensions of the island? If within the confines of a slab then I would think that there shouldn't even be a seam.