Not really. 1 IS a legal issue. 1 is not. HUGE difference, IMHO. If I were a Supreme Court Justice, and this were a case brought before me, I'd be making the same conclusions you're making Bt. However since the Mosque is neither a contitutional nor legal issue, those conclusions need not be made
In Obama's words, "let's be clear". This Imam has an absolute constitutional right and is completely withing all legal parameters to build a Mosque where he wants to, on private property. Does that make it the right thing to do, where he currently wants to put it? The appropriate thing to do? Hell no. It's gonna have precisely the opposite effect as to what he claims the Mosque will bring.
But legally, he sure can