Because maroons like these folks will pitch a fit. Other than that, there's no good reason that I can think of. And the sad truth is, people like that are convinced that nuclear power is inherently evil, no matter how safe you can make it - they simply don't believe it, and they'll resort to half-truths and outright deceptions to persuade others. In most other places, you can get around them with some work, but unfortunately, California seems to have a somewhat higher concentration of fruits and nuts than other states. And by the time they get done with you, your nuclear power plant will end up costing about six times what it otherwise should, thus destroying any economic advantage it might have had. Be sure to thank them the next time you get a $900 electric bill ;)
Because the design is an antique and smaller, intrinsically safe, gravity cooled, distributed units have lower line losses, are more secure, and easier to decommission. There is one being planned for installation in Alaska now.