Yeah, Optimus really wants to protect humankind. And he seems to really care about individual humans since he ordered his fellow Autobots to protect three human youths. But does he PERSONALLY care for humans? I didn't see Optimus even once in the show offering to give a human a ride home or take on their guardianship for even a little bit. He just seems to shove them off on the other bots. Now he may have his reasons. He is the leader probabely needing time for other issues. He may feel that having humans under his care puts them in more danger than under the care of his other fellow Autobots. His big rig alt mode won't blend in as easily in everyday society as those of Arcee and Bumblebee. (However, Bulkhead's mode isn't something you see everyday parked on the street either.) But one has to wonder if Prime may have another and less altruistic reason for not wanting to take on the guardianship of the humans since his Hub bio describes him as being caring but emotionally distant. I think it would be neat if in a future episode Arcee chastises Prime for shoving humans on everyone else and tells him that if he cares about humans so much, why doesn't he personally guard one himself. Well the show is going to delve into what it really means to be a Prime. Maybe being a Prime means personally caring about others instead of just caring about them from a distance. Maybe he'll really learn this if he ever encounters Elita One and really develops feelings for her.