I didn’t downvote you but fish sauce does taste strongly like rancid fish to some people, even in trace quantities. Nothing about that flavor profile is delicious. There is nothing stealthy about it either if you are one of those people; you can immediately detect that disgusting note on the first bite.

I love anchovies and use a lot of them in many of the dishes I cook (including tomato sauce). Fish sauce ruins everything it touches for me. It isn’t lack of exposure either; I lived on Vietnamese home-cooking for many years. I eat a lot of weird and pungent things but I have no context for why anyone would want to put that fish sauce in their food. Also, some types of fish sauce from around the world don’t have this effect for whatever reason.

I’m pretty sure from observation that it is gene-linked thing, like the cilantro sensitivity. While rare, even some Vietnamese people seem to fall into this set and it is part of their cuisine.

I'm just down voting a meaningless comment. 1T fish sauce + an unknown amount of tomato sauce could taste like anything from fish sauce to tomato sauce.