I don't know if this is going to help you answer your questions but here is some background information:
1. In Sweden you must be registered at an address for all purposes (taxes, health care, official communications, etc.).
2. On websites like MrKoll's, all you need is a phone number to find someone's home address (you can also find someone's phone number using their home address).
Based on these two facts, all the bomber planning the attack needs is a phone number to find out the address. If the victim is using a burner phone (which, by the way, have become illegal in Sweden since 2023, now all "kontantkort" or anonymous simcards can't be anonymous, they have to be registered to someone's name, and you can only do that with a valid ID), they can otherwise target one of their family members.
> Where is the evidence that the bombers used a data broker to find their target
The writing is on the wall. This is a free service. Why wouldn't they?
> removing this information from the public would have changed anything?
The problem is that these companies (like MrKoll there are others) are abusing the media license they have been granted, not only violating rights that have been well established in the EU (which Sweden is a part of) but also they are making an already vulnerable population even more vulnerable.
Grandmas and Granpas are being targeted by scammers with all sorts of schemes, and where do they get phone numbers and also a quick profile of the target? via these websites.
So yeah, removing this information from the public would change something, perhaps not necessarily to the gang wars, but for sure for the safety of the public in general (gang family members would be harder to find).