Why is my baby bunny crazy

so we have 2 rabbits, a 4-5 month old Thrianta male(neutered). and a 2 year old black bunny male(un-neutered).

we've been wanting to try to bond our rabbits, but for some reason the 2 year old un neutered one seems to be happy having another rabbit, where as the 4-5 month old one seems to hate the idea, everytime he is brought around the older one he tried to bite its face, my girlfriend got in the way of him attacking the older bunny today and he bit her finger, and leg.

seems to be the main time hes vicious, i just figured the older un neutered one would be more prone to being violent with the younger bunny. but for some reason its the exact opposite, anyone have any ideas why???

any advice would be greatly appreciated.
thank you.

When was the younger one neutered?

about a month to a month and a half ago

it's possible they just don't like each other (or rather, the younger one just doesn't like the older one)... M/M is probably the hardest pairing to bond, so it wouldn't be surprising for it to not work out ><

are you always introducing them on neutral territory (somewhere neither bunny normally goes? if not, that could make a HUGE difference.

Rabbit's are very territorial. When you put a rabbit in another one's territory, they can actually fight to the death. Although, the rabbit's personality has a lot to do with it. Some will easily bond with another bunny, others can take weeks. I have 10 bunnies. I have bonded 5 of them together already. I am now working on bonding the 6th bunny into the warren. For me, it seems easier to do the bunnies one by one. I put them in x-pens side by side. Make sure they can't bite each other through the holes. Once they start to groom each other through the holes, you can then try putting them together in a neutral territory. I use my bathrub. Since you are trying to bond two males, it is going to be extra difficult. I would think you would for sure need to have both of them neutered first. If they won't bond, you could try introducing a spayed female to the group.