"Eating goddamn fish" for me is what "eating goddamn dog" would be for you. Give me the capsule.
These have completely different tastes and consistencies... especially if you're talking about firm/frozen tofu. Cottage cheese is not an adequate substitute. Not to mention that milk, which cottage cheese is made of comes from cows, and many people have ethical objections to factory farming of animals.
"protein through meat ? Nah we have beans"
Again, many people avoid eating animals for ethical reasons (or health reasons)... and, again, these are not equivalent in taste or consistency. There are taste/consistency reasons why burritos and chili, for example, have beans in them and not just meat.
"Omega 3 by just eating a goddamn fish which is available in the grocery store ? Nah I am gonna eat some processed capsule."
Some people have concerns about consuming too much mercury when eating fish, and want alternatives because of that, others because of ethical reasons once again.
Are these all uniquely American concerns? I don't think so. Just consider Asia, where eating tofu has been the norm for a very long time. Vegetarianism is also very popular in India and some other parts of the world.
Tofu is pretty cheap (about $2.64 - $3 where I live). It is also very versatile.
Beans are very cheap whether dried or canned. You can usually get them for about $1 / lb and the price drops of course the larger the quantity you buy.
Oh and if you think beans are a good source of protein, why don't you talk to my friend: split peas.
The only example I can see you gave that would be expensive is the "processed capsule" for omega 3 supplements.
Cottage cheese ? Nah we have tofu,
protein through meat ? Nah we have beans,
Omega 3 by just eating a goddamn fish which is available in the grocery store ?
Nah I am gonna eat some processed capsule.