The capacity has been reduced, but pre covid the park never really hit capacity anyway. So even though the capacity has been reduced, there is pretty much the same amount of people they would get on a standard weekend. Mix that in with the reduced capacity on rides and social distancing, the park looks and feels busier than pre covid.
I really don't think they should be advertising the fact they have a reduced capacity, same with all the merlin parks. It's giving people the wrong idea that the parks are going to be less crowded when in reality, there is pretty much the same crowds as normal.