Raw cherry tomatoes or grape tomatoes would go along with raw carrots and raw celery and raw cauliflower and raw bell peppers and other raw vegetables on a crudité platter. Guess what “cru” and “crudités” means in French?
The point being that these are all vegetables that can also be served cooked. (Unlike lettuce which is ruined by cooking. I tried it once, blech.) But when dipping, you want that firmness and fresh taste.
It’s not a US thing, or anything special, you just seem to have an exaggerated idea of what the word raw means. Maybe you’re confused because it can also mean naked (“in Equus, he appeared on stage in the raw”) or chafed/chapped (“his nose was red and raw from the snowstorm”) or unedited/unfiltered (“the raw data suggests Hillary Clinton will win the 2016 election”). But in this case it just means uncooked/unheated. It could be sliced and spiced and still be raw.
Btw, we don’t default to cooked or canned tomatoes, we would specify those as well, for instance in a pasta or chili recipe.