I'm not certain I buy into the hard and fast line you seem to draw between religion and spirituality. Life is more complicated, I think. Spirituality often functions as a kind of "voice of conscience" within institutional religion, challenging the us/them way of thought and action, discerning the kinship of all humans, and reminding us God can not be housed within our structures.
Spirituality may well lead us to embrace life without the usual securities. It also may lead us back from forty days in the wilderness to speak a word of challenge to our religious structures even as we continue to attend synagogue. Genunine spirituality ultimately requires us to love the neighbor, even the ones within our religious worlds. At its best, spirituality enables us to see a little farther and deeper than our home religious culture. We may then challenge the tradition, hoping to nudge it in the direction of a healthier vision of God.
To put it another way, we function as neighbors who have gone ahead of the group, around the bend or over the hill, so to speak. We return to say, "Come and see what I found." We cannot control the response of our neighbors. They may listen politely yet stay put. Some may label us heretics and take up stones against us. A few may go and see for themselves. Generally speaking, I think it requires at least a long human lifetime for a significant percentage of any religious people to respond positively. Sometimes, it seems to require centuries.
I wonder if we despair, at times, because the pace of response is so slow in relation to the brevity of our lives.
The Third Commandment strikes me as a word from the God we meet beyond the normal boundaries. Perhaps it's a word directed not only to those who rather casually claim God's endorsement but most especially to those who travel ahead. If so, the message might be phrased: "Remain thankful you've been allowed to peep around the next bend in the road; take care not to claim you've seen more than you've seen."