Blame is a slippery slope. The fault is with the malware creators and them alone. They are committing the criminal/unwanted behaviour.
Top tier ad companies work very hard on this problem and if you check how many ads are run compared to just 1 being bad, it's a tiny fraction of a percent. Does it happen? Yes. Everyone on this site should already know there's no such thing as perfect security or a service that cannot be compromised given enough time/money. That's reality.
Please reconsider exactly who is at fault here for issues like this and hopefully you'll realize it's not just so black and white and this isn't quite a good enough reason to block ads. You can always use antivirus or malware protection software that's actually designed for this stuff if that's your primary concern.