You're having trouble with the concept of a "commandment," aren't you?
I suppose you think G-d was a big meanie for ordering the extermination of the Canaanites.
If the above weren't true, then would the reverse apply to you? As in, for example, would you endorse the concept of a trinitarian god, as truth? Yes or no?
If you have a problem answering this question, and if you have the capability to recognise that the same can hold true with another individual when it comes to their personal beliefs against yours, you will understand the importance of recognising that such beliefs are, you guessed it, personal.