Found your article while googling for Amazon hacks.
It seems Amazon has gradually implemented changes that discourage the ability to effectively search by Department. This is particularly evident on the mobile site which presents preferred groups/distractions once a primary department is chosen and requires scrolling all the way to the bottom of the page to continue. They’ve also suppressed listings categories and links from item details.
Do you believe your issue may have been a function of improving search results on Amazon’s own site vs redirecting to item links? That distinction may be relevant given the lenghty existence of sites like Camel that function on price but provide improvement to search results.