It is more accurate to say that active attendance at the New Mass is inherently evil.

It is more accurate to say that active attendance at the New Mass is inherently evil.

Why isn’t passive attendance also evil?  Are Catholics allowed to passively attend an abortion?  Or a satanic mass?  

Why isn’t passive attendance also evil?  Are Catholics allowed to passively attend an abortion?  Or a satanic mass? 

Because ... that's what Catholic theologians hold.  Do you even understand the term "passive attendance"?  You clearly do not.

It just means that you happen to be there.  Let's say some priest shows up at a Novus Ordo Mass to study what they're doing, so he knows better what to say about it to the faithful.  He's not PARTICIPATING in any way, but just there to study it.

What's at issue isn't just happening to be there, but your participation.  Let's say O'Keefe or one of those other guys snuck in to get some video of an abortion.

With regard to things like non-Catholic Rites, theologians have long understood that many of those Rites have dual purpose, such as, say, a funeral.  While one aspect of it might be religious, the other is simply social, where you're paying respects or going to offer emotional support to the family, etc.  As long as you do not participate in the religious aspect of it, and give no reason for anyone to believe that you're participating in it, you're permitted to attend the funeral, or a wedding (if it's valid).

There are other things, such as a Satanic Mass, that there's no legitimizing dual purpose to be there, but even then perhaps you went there to get evidence for the authorities to bust it up, or to docuмent it, or even that you're going to say "surprise", pull out a firearm, and put an end to it right there.  But, short of some extreme scenario like that, there's no general legitimizing dual purpose.  That's where DOUBLE EFFECT comes into play.  I can go to a funeral to pay my respects and offer emotional consolation (provided it doesn't entail endoring theological error), with the undesired secondary evil effect that I have to be there passively at a non-Catholic religious Rite.  That's where your comparison fall apart, since the legitimizing dual purpose for being there would have to be extreme and unusual (such as docuмenting or attempting to bust them), vs. with a funeral the dual purpose is simply part of the nature of the thing.