We can frame violence in ways that justify or invalidate its righteousness.
It depends on how you define "wrong". But there are universal truths. If someone tries to kill or harm you it's considered just if you harm them in defense.
We dont know Luigi's legal defense yet but my guess is his attorney will argue self defense. If so the justice system now has to sort out whether this was self defense and in that sense it will likely be considered wrong.
The permissions on their extension allows for them to read site data so they definitely could operate as a data broker. However their tos has no mention of any data sharing so you are likely correct that they just take a commission. Great site imo