They don't understand the feeling, because they have not had it shown to them in thier developmental years. They are emotionally disabled or impaired.
Ego. And subconscious self defense mechanisms. They're just not open to it. You can't feel it if you refuse to touch it.
Because they have learned to block them. Most likely due to the fact that they are very emotional people. Or, less likely; sociopaths.
some people just don't want to feel an emotional connection as this can cause problems and feelings can get hurt...
Different people have different reasons, one answer does not fit all...
i wish i knew, then maybe i could fix it
They can feel it... maybe they don't agree with it.
Like they don't agree how they feel... so they don't pay attention to how they are 'actually' feeling and they pay attention to how they think they 'should' feel. And then they aren't in touch with their emotions, and don't feel an emotional connection.