Ok, time to debunk shitty smug anime character logic.
1. If "weakness is a sin", then Abeno should have been long dead by now, she was powerless and far weaker than the rest of her family, so she should have been dead for far longer than kaichou here
2. yakuza organizations generally exist because of three things, though not necessarily all three things, 1. intimidation. most yakuza organizations are intimidating enough to deter people from just going in and slaughtering them. 2. ties to government. some yakuza organizations, mostly the ones that are more like mafias than drug dealer/assassination organizations, have ties to government, either having intimidated some officials into not arresting them or straight up having yakuza or yakuza sympathetic members be officials, making them significantly harder to deal with legally. 3. scope. most yakuza organizations are vast, multiregional organizations, or they have other branches in other territories, meaning that there is the possibility that a neighboring yakuza organizations or family members of those disposed of could come and kill you, meaning that you would have to potentially kill a lot more people to not be targeted, meaning that the likelihood of 30 riot gear equipped police getting away with slaughtering an entire yakuza is... miniscule