Is "more ethical" really enough if you accept that plants can suffer? You're still essentially saying one group of living things' suffering is acceptable to you. Isn't that like saying the holocaust of the Jews was bad, but the holocaust of the Roma at the same time was fine because there were fewer Roma than Jews? Does "less" matter when we're talking quantities so massive?
I don't think there are easy answers to any of these questions. Not if you want to approach them from an honest philosophical level.