Your first example could have a different explanation, assuming she is the one that more often does the laundry. Ordering clothes by type is cognitively easy: a shirt is a shirt, shorts are shorts. When you have a stack of freshly washed clothes, sorting them according to type is so trivial it is a thoughtless process.

However, sorting according to use case is more involved. For each piece of clothing in the clothes pile, the clothes organizer must think of how this particular piece of cloth is used. Is this just an old t-shirt? Or is this particular old t-shirt out of favor with my husband and so he uses it for his workout? Or should it go in the pyjama t-shirts pile?

So writes seem to be much more costly (cognitively) when organizing clothes according to usage rather than type (if these clothes are not your own in which case determining their usage does seem trivial), and your wife may be optimizing for it (again, see initial assumption)