The hoods supplied with some lenses seem to be larger than necessary. That is, they step up the diameter and then make it longer.
The most egregious example I know is Canon EF 17-40L f/4 (or EF-S 10-22, which uses the same hood, as far as I remember):
Sigma 150-600 made a special effort to raise its hood on stumps:
Why? Geometrically, it seems to be pointless: only the angle should matter, so a shorter, smaller diameter hood would do just the same job, while being much more compact (and could still be mounted in reverse for storage). The EW-83E was such a menace when I had to use it; it could only be packed away separately. The same with this Sigma...