Actually the word lord is also used for revered one(honorable king) . SGGS is always in preacher mode. As you have noticed that preachers use examples to prove the point. in same way SGGS has used the Krishan and RAM(King) as example as both were and are comman and Popular characters. The idea of using RAM and Krishan is to Preach the Goodness and Nobility. am not so expert in Sikhism. so E&O.E