I'm just going to answer your questions pretty much one by one.
1. Kenny did choose to save his son which is understandable but the fact once he had done so he didn't even attempt to save Shawn, he just ran away like a coward.
2. Kenny wasn't in the wrong here. His son was being threatened and was assumed to be bitten (which he wasn't) I'm sure if it was anyone's son they would do the same.
3. Kenny tried to force his decisions onto other people which Kenny I don't think made a good leader in any way at all. Everyone should have had a say in what they wanted to do rather than Kenny making everyone do what he wanted. Although he did have a good point that all the resources in the surrounding area had been drained.
4. I believe by attempting to save him you're making the right decision, but I also agree with killing him because if Larry had came back then that would of doomed them all. The truth is saving Larry was the only human thing to do at that time, as sad as it sounds I have morals (even in game play) I believe in keeping the humanity and by saving Larry or attempting should I say is sustaining that humanity. Other people can feel free to disagree but this is just what I personally think.
5. If Clementine was bitten I'd do the same as Katjaa, I'd spend the last amount of time I had with her. I know what would have to happen and I know it would have to be taken care of but I wouldn't kill myself like Katjaa. Kenny was hurting throughout the process of Duck worsening. He knew what had to happen but he was in denial of it because of what had happened in Episode 1 - A New Day. The incident with Shawn, Lee also points this out in Episode 3
6. I agree with this only very dearly though, I believe in forgiveness but I don't believe Ben should have been killed but cut loose from the rest of the group. He should of just been dumped, Kenny had every right to be upset/angry at Ben but the death sentence he was threatening was unfair. I think if you're going to live in a new world then you've still got to have some humanity, that's the only way you'll get by.
I hope I helped answer your questions. Overall not everyone hates Kenny as much as it seems, a lot of people are quite fond of him. But, my personal opinion I think he's a coward and selfish, there's been too many occasions when Lee has been in danger and Kenny hasn't stepped up and helped. (I think this is when you disagree with him though, not sure) Either way I've never been fond on Kenny.
~Bloss