The display of some emotions can be more harmful than others.
For example, road rage has resulted in countless hurt or killed people.
Someone who is happy to see their beloved relative or friend and shouts for joy would not be harmful.
Making a pass a co-worker one finds very attractive could lead to them getting fired with accusations of sexual harassment.
There is clearly a real NEED to CONTROL harmful emotions, since acting on them can do lasting harm.
Crying when someone dies (as avidbiblereader pointed out) is an emotion that Jesus exihibited, but tears in and of themselves are not hurtful.
Clearly, it is lazy thinking that eventually leads some people to act on harmful emotions.
Our values should never be compromised by harmful emotions.
It takes real conscious effort to identify and control harmful emotions.
YC