I assume they meant they were hashing the response rather than hashing the request. Then you don't have to keep the entire response around for comparison, only its hash.
Content on the page with slug `{company}-hockey-tickets-2016-season` changed, not the slug itself.
I think mhb's point is that the size of the request content is so small, it can be compared byte-for-byte directly instead of hashing and comparing hashes. Many of us have a kind of muscle memory where we always hash everything for comparison, but for small data there is not really a point.