They can't enter and search your house whenever they want. They can ask and you can let them in, which is what happened.
Exactly. The cops were not kicking in doors, what is wrong with people?
Who in their right mind would say no under those circumstances? Even if I knew the guy wasn't in my house I'd still let the cops do their damn job because I'm not an asshole (and I'm not saying if you refused them that you would be). Hell the thought of them searching it would actually give me some extra feeling of security in a way. In fact, your probably giving the cops some peace of mind as well, helping them eliminate possible locations where a freaking domestic terrorist may be hiding.
Tell you what, when the people of Boston who had their residencies searched start to bitch about their constitutional rights being infringed upon in order to insure their safety, let me know. Because at the moment, they all seem to be pretty damn jolly with the way their law enforcement handled things. If they don't have a problem and don't feel as though they were violated in any way, then I don't either.