My son has recently started saying "I hate..." a lot and I'm struggling to work out the best way to handle this. For example "I hate going to sleep", "I hate doing a wee", "I hate walking", "I hate holding your hand" and "I hate going to pre-school". The funny thing is, I know that for some of those things, he actually really enjoys them, and for others he isn't bothered either way. I'm trying to work out an appropriate way to respond that won't escalate the situation - I don't want him to end up refusing to ever do another wee! - but that still acknowledges the feelings he is expressing, even when I believe that deep down he doesn't actually feel hate.
It sounds like one of those many phases that children go through, trying out a new thing and testing your reaction. I always found it best with my kids to not acknowledge the negative attitude but to continue to project your own positive one. Don't try analyzing or negotiating him out of it. Show him simply that good behaviour and attitude is acknowledged and negative behaviour is not. He'll soon work it out. Good luck!
If you're gut feel tells you he doesn't actually 'hate' the things he's describing it's likely a phase of him testing the water. I'd focus on the positives of all the situations you can....so next time you're walking and he hates it, reflect on something good about the walk. So maybe it could be that you spot a bird, or notice something else that's cool....you can then reflect on that saying 'I know you said you hated walking, but wasn't it good to have that walk so we could spot that butterfly/bird/dog etc'. Many situations work well with positive reflections and at other times you might have to simply ignore the hate statements. I once tried to get my then 3 yr old to describe why he hated certain things that he was citing that day and quickly realized it was all just to test the boundaries with me. It gets very frustrating but it passes quickly. Reward charts or positive reinforcements definitely helped more than trying to analyse the behavior in my case.