Because some people love Jurassic Park and want to be immersed in the fantasy that they are in a real Jurassic Park while in that section of the park, and the Discovery center is one of the most iconic parts of JP and one the key parts of selling that illusion.
While I'm feeling cautiously optimistic that this coaster will be done right, I think it'd make you a little nervous too if, say, Universal announced they were building a roller coaster that goes directly in front of and around Hogwarts. Obviously, JP as an IP has more leeway for this sort of thing since it's already sort of a theme park in-lore, but something like the Flying Dinosaur coaster in Japan which just leaves twisted coaster tracks everywhere kills the immersion and constantly reminds you of the artificiality of everything.