This "... แต่พอหมักปลาร้าพวกมันบอกว่า "แหวะ" ยกเว้นคนอีสานที่หมักกินมานานหลายพันปี จนติดเป็นนิสัยประจำชาติิไทยไปแล้ว..." is not accurate. There are

Garum - Wikipedia https://en.wikipedia.org/wiki/Garum
Garum was a fermented fish sauce used as a condiment in the cuisines of ancient Greece, Rome, and Byzantium. Liquamen was a similar preparation, and at ...

Surströmming - Wikipedia https://en.wikipedia.org/wiki/Surströmming
Surströmming is fermented Baltic Sea herring that has been a part of traditional northern Swedish cuisine since at least the 16th century. Just enough salt is used to prevent the raw fish from rotting (chemical decomposition). A fermentation process of at least six months gives the lightly-salted fish a ... (Swedish: förordning) that would prevent incompletely fermented fish from ...

Kiviak - Wikipedia https://en.wikipedia.org/wiki/Kiviak
Kiviak or kiviaq is a traditional wintertime Inuit food from Greenland that is made of little auks ... rather than auk. Eider does not ferment as well as auk, and gave those that ate it botulism. ...

Now look at

Ketchup - Wikipedia https://en.wikipedia.org/wiki/Ketchup
Ketchup is a table sauce. Traditionally, recipes featured ketchups made from egg whites, mushrooms, oysters, mussels, walnuts, or other foods, but in modern ...

Worcestershire sauce - Wikipedia https://en.wikipedia.org/wiki/Worcestershire_sauce
Worcestershire sauce frequently shortened to Worcester sauce, is a fermented liquid condiment of complex mixture created by the Worcester chemists John ...

We can see that what we are not good at is 'branding' and 'marketing' - nothing wrong with 'fish sauce' nor 'fermented fish'!