Just to be clear, I'm not saying a single food can provide all your nutritional needs. That's not true of either vegetables or meats. I'm just talking about protein. There are so many misconceptions that it's ridiculous even with medical and nutritional professionals.
Sorry, that's pretty much BS. Do you even know what is meant by "complete" protein?
Rice is on the edge for protein if it is the only food you eat, but it's not insufficient. Then there's the issue that it's never the only food you eat unless you are an idiot or have a compulsive disorder. If rice is the only food you eat you have much bigger problems than worrying about protein.
But just like with many issues, people believe what they want to believe in spite of the facts. I will admidt it is hard to get the facts. To assure you are getting the 9 essential amino acids each one need to be measured/calculated in the context of the calorie intake, not vs. the volume or the weight of the food which is how it's often presented. Then there are the many units in use and it gets to be a real quagmire requiring a spread sheet to make sure you have it all straight.
Still what? People want to eat meat because they like the taste. They mostly don't really care about nutrition or they would eat a fraction of the meat they do since much less meat is much more healthy. You don't need to give up meat to get the advantages of a vegetarian diet, but most people have little interest in doing what is best for them. They'd prefer to eat horse paste after they get sick.
Don't know. I haven't tried to make my own ice cream. I don't think that's actually the issue. Some things that are imported get taxed very heavily, plus the cost of importation. I don't know if ice cream is made on the island or imported. I'm told there are many things they do not grow on the island in sufficient quantities which includes most meat. I've traveled a portion of the island and seen very few farms of any sort.
I was told that at one time there were a lot of essentially subsistence farmers who grew enough excess to feed the island at least partially. A new governor promoted the construction of factories creating lots of new jobs. Most of the farmers abandoned their land for the better life working in the factories. The result is the vast majority of the food is imported now.
Maybe ice cream has a much higher tax than other foods. Don't know. But at $7 a carton for store brands or $6 a pint for Ben and Jerry's, I've been nearly ice cream free for three months. I do have a Klondike bar or two when I come back to the mainland.
A quick google search shows there are many dairies in Puerto Rico, but much of the feed is imported and in the higher temperatures the cows produce less milk. I haven't noticed it's actually much hotter than my hometown of Frederick, MD in the summer time and that is still a significant dairy community. Maybe the cows pump out a lot more milk in the winter.