I have been tempted at times to start a thread "in defense of Ennis." I think if Ennis had all crummy qualities, Jack probably wouldn't have loved him and we wouldn't either. He's got great qualities, but they're harder to pin down than Jack's.
Yes, in defense of Ennis, though I don't think he needs much defense, he has very good qualities: his loyalty to and love for Jack in strong, his tender care of his children is deep, his willingness to defend those he loves is impressive and sometimes even forceful, his sense of humor shines through clearly, but all of his good qualities glow through a heavy layer of sorrow, hurt, fear and anger.
Ennis is a fine man, but he really needs help with the trauma of his boyhood, issues of abandonment and his fear of intimacy. I mention again that Ennis is one of the "walking wounded" and point to the horrible experience of his father exposing him to the murder of Earl, Rich's lover, when Ennis was just nine years old. That, and then the early death of his parents, really hurt Ennis.
The poverty he was born into doesn't help either. We all struggle , but some, like Ennis, have more to contend with in life. Still he is tenacious and determined to make a way even if it's meager and humble. Ennis also has a great love of nature and the wilderness that I can relate to myself and I identify with Ennis's trauma having had a great deal of it in youth, I know what if feels like and how hard it is to overcome. I identify with Jack more, but there are very good qualities in Ennis that, as mentioned below, are reasons for loving him. They're not that hard to see, but you do need to spend time with Ennis to see them. Jack sees them. I think the more time spent with Ennis, the more one would grow to love him.
Part of the dynamics of the drama of BBM is the tension of Jack seeing and loving Ennis and wanting more time with him against Ennis's inability to give that time and satisfy that need in Jack, but that is a whole different topic... for another thread maybe? I must say, to end this, that both men are good people, likeable, lovable and decent and Annie P. sure created believable human characters, didn't she!
Peace,
Rayn