"Better to be safe than sorry"
That's simply nonsense.
If your product doesn't work, and produces a large number of blatant false positives, which prevents legitimate businesses doing actual business with VM customers, then it's better to fix the bloody thing, or at least quickly address each false positive as it comes in.
Why is this only an issue with WebSafe? Why don't I see other ISPs blocking legitimate, safe websites?
All I've seen is deflection and denial on the part of VM.