Deep down the people are much the same. Amend your ways and your doings, and let me dwell with you in this place. The Temple worship had been cleaned up, the old sacrifices were being offered once more, and there was a real sense of joy that the nation was back on the right footing with God. But Jeremiah says to them don't trust those deceptive words. There's more that's needed.
Religion is more than places and buildings and words.
Sure it's important to come together with others to worship God. It's important that the places we gather in be conducive to worship. It's important that the words we use are fitting, that the hymns we sing help us raise our voices in praise to God. But if that's all we do, our religion is empty. Standing in a church singing hymns doesn't make us any more holy than climbing into a kennel and barking will make us a dog.