The only reason they add dyes, outside of baked goods IMO, is because they've used so many artificial ingredients, fillers, and preservatives that the resulting food product no longer looks appetizing. Whole, fresh food has never needed dyes added to it to be enticing to our monkey brains.
Carmine is better known as Red 4 these days. Doesn't have much taste. Saffron adds basically no taste in the amounts typically used for something like Saffron rice. Squid ink again, mostly for the striking color. The taste isn't particularly great.
Turmeric can go both ways, but the ground turmeric that's historically common for preservation reasons is much less flavorful than the fresh root. It's mostly a color thing.
Of course, we can also just open up a medieval cookbook to see what they say. The Forme of Cury is a nice 14th century example that's available from Gutenberg:
https://www.gutenberg.org/ebooks/8102
As to colours, which perhaps would chiefly take place in suttleties, blood boiled and fried was used for dying black. saffron for yellow, and sanders for red. Alkenet is also used for colouring, and mulberries; amydon makes white; and turnesole [for yellow]
Alkanet is commonly used today for Rogan josh, but historically would have been more known for rouge and dying wine. A Mediterranean cookbook might have instead chosen amaranth for the same purpose
You need so little tumeric or annatto to color food and they impart so little flavor in so many applications that the reason they are used is very obvious.
Fruits and vegetables from a few hundred years ago would be almost unrecognizable and unpalatable to modern consumers. The colorful, delicious, and durable fruits and vegetables of today are the result of lots of work and selective breeding.
Most fruits and vegetables in grocery stores taste pretty bland. They're bred more for appearance, shelf stability, regularity, and transport rather than taste.
There are legendary varieties that are lost to time. Occasionally we rediscover them, and we get to compare. Usually the modern industrial varieties are pale imitations.
Although you're free to like/dislike whatever you want, calling other people's food vile seems kind of mean. There are plenty of old/ancient foods that look exactly the same as jell-o
warabi-mochi, nata-de-coco, aiyu jelly, kokum, annindofu, kanten, blancmange, to name just a few
Jell-o is a byproduct of the meat industry, none of what you listed seems as bad nor look as bad as a mass produced artificially colored and artificially flavored blob of pork gelatin seating in a plastic cup.
If anything I'd say my take is less insulting to these other dishes than you are by comparing them to jell-o
Wild salmon have their characteristic color because they are eating organisms that contain the naturally occurring Astaxanthin. Farmed salmon subsist on grains, fish oils, etc and come out looking grey unless pigments are added to their feed.
interesting, the Salmon I have caught has not been as colorful- I mostly fish in the rivers though
edit: it looks like that vid had some steelhead (trout) mixed in? This is more like what I have seen, but the color is even more "dulled" in person https://www.youtube.com/watch?v=e09UmeqAd4g
