Assalamu alaykum,
Yeah Suicide bombing is wrong, as is any other sort of bombing or killing of civillans, whether carried out by Non Muslims or Muslim. As a sidenote and to put things in perspective, suicide bombing is mostly carried out by non Muslims, for example in srilankan tamil tigers, and of course many countries bomb under the guise of "collateral damage". However, this of course does not make such actions justified.
You will need to ask a scholar who knows about that. I dont think there is any evidence that death of the enemy is mourned. Because they fought against the Muslims and carried out atrocities against the companions and their families. Clearly we can not say something without any evidence or knowledge. On the other hand of course, we are not saying the Muslims were joyful at spilling blood and fighting just for the sake of fighting.
The evidence shows the Prophet
fobid the killing of innocent life, and even spoke about the sanctity of nature such as trees.
Sunan Abu Dawood:
Narated By Rabah ibn Rabi' : When we were with the Apostle of Allah (pbuh) on an expedition, he saw some people collected together over something and sent a man and said: See, what are these people collected around? He then came and said: They are round a woman who has been killed. He said: This is not one with whom fighting should have taken place. Khalid ibn al-Walid was in charge of the van; so he sent a man and said: Tell Khalid not to kill a woman or a hired servant.
The Prophet
was the most compassionate man, and the Quran clearly states that if we are at war, and the enemy we are fighting incline towards peace and want to stop fighting, we too should do that.
90. Except those who join a group, between you and whom there is a treaty (of peace), or those who approach you with their breasts restraining from fighting you as well as fighting their own people. Had Allâh willed, indeed He would have given them power over you, and they would have fought you.
So if they withdraw from you, and fight not against you, and offer you peace, then Allâh has opened no way for you against them.