My $0.02: there's a gradient between listening charitably (e.g., assuming that your interlocutor probably meant something sensible, and therefore that the senseless thing you heard doesn't accurately reflect their meaning) on the one hand, prioritizing your time (e.g., disengaging from discussions that seem like a waste of time, either with silence or with cached politeness or whatever) on the other, and refusing to challenge error (e.g., pretending something is reasonable because pointing out the flaws with it feels rude) on a third.

Only the third of those seems like a problem to me.

Where you draw the threshold of too-much-in-that-third-bucket is a really up to you. You're under no ethical obligation to prompt non-cached thoughts from everyone who talks to you.

I have developed a similar habit over time. I am often the "smart guy" in my social enviroment (I'm not particularly brilliant, but neither is my usual enviroment), and I can often identify major flaws in other people's reasoning. Despite this, I very rarely point them directly out. Social conventions usually state that this behaviour is considered unpolite, indirectly implying that the other person is dumb. It can be even worse if the other person is emotionally attached to the thought. So, unless I am discussing with a very close friend, I usually restrain from making meaningful comments.

This is connected with the first post in this thread. Conversation is easier when you take turns, setting up your partner to ask obvious questions.