Well, I see where you are coming from, but I would disagree...I know that Microsoft isn't always great and did lots, and lots of weird things in the past, but that does not mean it's always at fault.
Just because a legacy driver was not flagged as incompliant for some time, does not mean it does not become incompliant when the grace period has expired.
Core isolation has been around for quite some time and is a security feature that absolutely makes sense.
If Line 6 decided that a machine running their software cannot have core isolation activated, because the software needs direct access to hardware resources or the performance impact is too big, it's their job to clearly state this so the users are aware (...it will also cause issue with newer machines that have CIMI turned on by default).
At least on my machine the only drivers that are NOT compatible with Core Isolation Memory Integrity are the ones from Line 6...is that different for you?
...so, at least from my point of view, the responsibility to solve this issue lies with Line 6.