Hey mate, it's not that people hate it - it's just that it isn't very healthy or safe for the snake.
Firstly, if you're feeding them mice from the petshop that haven't been frozen then you don't know what sort of bacteria or diseases they could pass on to your snake. I've bought a mouse that was infested with mites from a petshop before, so yeah... at least if you were buying them, killing them and then freezing them there's less chance of something like this happening.
Secondly it is unsafe for the snake. Mice tend to attack their attackers and can sometimes give a damned nasty bite. This bite may become infected and that may mean a whole lot of trouble.
I'm really not trying to be mean or anything. It really is just a whole lot better to feed frozen. I think it may even be illegal to feed live in some states unless the snake was under threat of starvation. Not too sure on that, but I've heard it quite a lot from a few sources. If you're having trouble getting your snake to take frozen there's a lot of solutions to get them to feed....
1. Braining - You stab open the mouses skull and dangle it around in front of the snake. This is a sure fire hit. Just keep nudging it up against the snakes nose if they don't take straight away.... eventually they will get annoyed and will strike at it, then realize they want to eat it.
2. Scenting - Not the best option, but if you can get yourself a hold of a skink (without harming it) to scent the thawed out mouse with, go for it.
3. Leaving the snake with the thawed mouse overnight.
Also, how were you defrosting them?
Pros of feeding frozen:
1. easy to store
2. healthy
3. safe
4. and more humane
I'm not just saying this to try and sound like I'm attacking you or anything, and I'm sorry if it sounds that way... just giving you some info.