What do you mean by teach? Say love one another every Sunday morning for sixty years? Where's the example of that love in their lives? Smiling a lot and saying bless you brother a lot while in church and then beginning to feud in the parking lot is not love or brotherhood.
Also, the Christian version of love is a problem for me. I calls its God love, a god that is intolerant, harshly judgmental, unjust and merciless in its punishments, and demanded a blood sacrifice in order to not have to torture all human beings. I have a better description of what love is, and it's not that.
Actually, the Humanists have the inside track there. While the major Abrahamic religions are arguing over just how much misogyny and homophobia is enough, humanists are tolerant and inclusive, and they don't just give it lip service. Humanists teach by example. They walk the walk. In the meantime, here you are promoting religions for this task, a task they've always failed at.