The seaweed covered rocks are more comfortable for them, it seems. This location at mid-tide is reliable for seal spotting I think because of the thick cover of seaweed. They just rest here, they can't move very well on land. They can also easily and quickly slide on the seaweed back into the water if necessary. Like when photographers' boats drift too close. I don't mind the background, it's what the New England coast looks like, and I grew up around it. I think the seals stand out against it.