me_irl

I mean, it's reasonable to say they could have done something and failed to do so. However, when you start to dig into what they could have done, it's hard to think of anything particularly effective and easy to see why they could have been convinced into inaction. So you could say they made a mistake, but were not fully at fault. The ones at fault are the ones who have been convincing them.

I like to say that responsibility isn't neatly divided up into percentages. Someone can be fully 100% responsible for something that happened, but other people can have some minor responsibility also. There's no threshold between being responsible or not, either, it's a sliding scale. When assigning responsibility and blame it's important to remember these things.