They are based on denmark's guidelines, which as you know is a very cold country.

One of the vaccines made strictly optional was for dengue, which is not really a thing in denmark since I think they don't have that many mosquitos due to weather.

However, in the US, mosquitos and tropical weather are common for a large part of the population.

Point being, a huge country with a huge variety of climates and diseases shouldn't follow the lead of a small country with a fairly homogenous weather and disease pattern.