It's a question about the scholarly interpretation. Except in the case of a catastrophic end, we'd expect any sites we find to be either refuse or discarded material. Ostensibly, a well-made handaxe would be taken from the manufacturing site and used until the blade was too chipped, worn or broken to be useful and discarded elsewhere.

The paper says that the handaxes found all show very similar construction. Is there any evidence as to why these similarly constructed tools were discarded or left at this site?

I don't think your joke is helpful.

Are the handaxes we find at these sites the errors/mistakes or were they making tools correctly and throwing them away for some reason

Domestic sheep are descended from Mouflon which still exist today. Mouflon do not have fluffy wool like modern sheep. They do however have a winter coat which they will grow if the temperature drops low enough that they shed each spring.

Early mouflon were probably treated similarly to the ibex (the ancestor of modern goats) when first domesticated. They were smallish hoofed mammals raised for their meat. At some point, a mouflon was born with a genetic mutation that made their winter coats longer and woolier. Not quite to the point we see them today, but definitely shaggier. Early shepherds realized that this hair could be collected and spun into threads.

At first, this wool was likely seen as a bonus. Shepherds would be raising the sheep anyway and as the sheep matured and fattened up, their wool could be collected and traded or used each spring. This made woolier sheep more valuable because each animal could provide extra value throughout its life time. This encouraged shepherds to select for the wooliest sheep and over time the wool grew thicker and longer, the mouflon began producing it year round instead of only in colder months and soon the value of the wool greatly outpaced the value of the meat, especially in colder climates.

As a result, the main use of sheep shifted from a source of food to a source of wealth.

Typically, animals like sheep and goats were raised in areas with less arable soil. Their native habitats were arid, mountainous and rocky and unsuitable for farming. Sheep and goats could graze on the coarse grasses and navigate the rocky terrain, and so humans could use them to extract sustenance out of a landscape that was otherwise unsuitable for growing crops.

Over time, herders selected their animals for different traits. Modern goats often produce milk and are capable of consuming many different foods. They don't require a ton of space and are ideal for being raised by a single family in small numbers.

Sheep herding followed a different path; they began to be raised on otherwise arable land because the value of their wool would enable a shepherd to buy more than enough food to support a family.

So, this study adds to the existing body of work by noting that the bitter alkaloids in the shells of the cooked seeds were soaked and/or boiled rather than deshelled completely. The authors suggest that deshelling would be easier and more efficient at removing the bitter and astringent compounds and conclude that this indicates that the ancient people preparing this food intentionally used the less effective method in order to retain the bitter flavor.

The title is not referring to any additional seasoning in this body of work, only that the bitter flavors in the food fragments studied were not completely removed.