This unfortunately is the nature of debate. You have to resist the urge to simply call your opponent "irrational". If they are lashing out at you, remember you appear exactly the same to them. It really is somewhat disrespectful to blame the other person for not falling head over heals in love with your idea. If you really do wish to reach someone with something useful take them calmly through the logical steps while being yourself open to influence and possibly a whole different view of the subject. This is true even and especially the more irrational they appear.