According to a post from another staff here, they said, in bold, that they are aware of the issue and not OK with it. But now you're trying to excuse it as acceptable. Is SE really going to go in this direction? Is it going back on the statement that it will prevent this from happening in the future?
From the linked post (emphasis in original):
Thanks for letting us know about this.
We are aware of it. We are not okay with it.
We're trying to track down what is doing it and get that mess out of here. We've also reached out to Google to enlist their support. I'll be honest: it's late in the day and we're unlikely to get this resolved today. But we've reached out and hope to get it fixed ASAP.
I don't like seeing Stack Exchange excuse malicious ads which fingerprint user's browsers.
You say that you were told by the ad company that this is part of fraud prevention. That is not correct. The AudioContext fingerprinting (along with other forms of fingerprinting that are harder to detect) that they are doing is not used to detect whether or not an audio player is present, but to uniquely identify computers due to quirks in how audio hardware operates. It's designed as a cross-browser and even cross-operating system tracking technique that, unlike cookies, cannot be deleted by the user.