The sand worms in Dune are gigantic creatures. Confirmed sizes reach up to 450 meters long. And in the wiki it says "Some people believe that worms from 700 to even 1000 meters existed in the southern pole regions, but this could not be confirmed"
In all cases the sand worms are huge. They are territorial and defend their territory against other worms, which makes sense. They also attack spice harvesters which also makes sense because those things are big and loud. Same with ornithopters or large things in general. It is conceivable that large things could be considered potential adversary or predators. Alright.
However humans or human sized creatures or noise also attract the worms? Which I'm not sure makes much sense. It's like a lion or rhino rushing to defend their territory from...a mouse or pigeon. What?
I understand they are a bit mysterious and I'm not saying it's done badly in the book or anything similar.
I'm talking about humans without shields, since they are driven mad by shields. Also they don't actually eat humans or metal contraptions. About their diet:
The main component of the sandworm's diet was sand, and other inorganic and dry components of the Arrakis crust. It is also believed they sifted the sand-plankton for nourishment.
I'm just asking: Is this behavior biologically probable/possible if they existed and followed laws of biology without any mysteries, would they still want to attack humans, human sized, and possibly smaller sized creatures? If it is possible then why?