I don't know how keen you are on almonds, but I used to make my own almond milk all of the time. I thought it was really good. I don't think it tastes like milk, but possibly a suitable substitute in hot chocolate? I didn't like the store bought stuff, though.A few reasons.
I'm not keen on making cows pregnant in order to be able to milk them.
There is an intensive but rather antiquated milk farm close by and I've spent enough time there (they have chickens) to know that the setup there is what I would consider as cruel so I don't like that.
I should for health reasons eat less dairy produce. However, that's quite difficult for me given I don't eat much meat...basically it means proper cooking and I don't like that either!
I'm going to check the alternatives out.