Earlier quoted context omitted.
What's wrong about being against one religion in particular. You can be "against" a particular religion all you want. But you have absolutely no right to prohibit anyone from practicing that religion simply because you don't like it. Including the "practice" of getting together with friends in a room or a building, and posting a sign outside the door saying this is what you do.
Churches have special status given by the government. This means I should absolutely have a say how many, what kind and where they are built. It's not about home meetings to read the Bible after dinner. It's about special status institutions which influencen the areas they are built in.
Then maybe the problem is the messed up laws providing that "special status" then. But that doesn't mean you can (even under those laws) category ban a certain group from building any churches, anywhere.
Which is exactly what Britain First is advocating.