Undeniably true.
The problem there, though, is that it has become like the old saying that "No one ever got fired for buying IBM." Except in this case, no-one ever got fired for blaming something on Marten's passivity.
So the argument frequently goes (explicitly or implicitly) something like this:
"So-and-so is really screwing Marten around."
"Not really. Marten is fine with it."
"That's only because he's so passive."
Undeniable, right? We all know he's passive.
Well, because he is passive, it can be hard to distinguish between Marten suppressing his feeling on the one hand, and him genuinely not being offended on the other. And we can only use our own feelings on the matter to determine the situation one way or another. Hence the disagreement on the forums.
So while I acknowledge that the people blaming Marten's passivity may sometimes have a point, it's important to remember that just pointing out that Marten is passive doesn't prove anything one way or another. It just leaves the door open to varying interpretations.
To get back to the current situation, I don't think Marten is being passive - he's being quite straightforward in his approval of Tai and Dora's new relationship. I will continue to take him at his word until I see some evidence to the contrary.