Are you the bands musical director? If so, leaving may be the best option, if they question your direction. If not, read on.
How would you respond if the drummer requested you to play your bass lines differently? Sounds like typical musician egos in play. The ideal channel would be to talk with the director/band leader and let them address it.
I actually welcome input and direction, no ego on my part. I've been playing music a long time, and as long as I'm alive, I'm still learning my craft. You may be correct, in that I offended his ego, but I'm normally surrounded by musicians who are more confident and would not be offended at spitballing suggestions while learning a new song.