engagement always trumps my fear or discomfort.
Agreed. (But you and I are social-dominant - I wonder if other INFPs would feel the same?)
However after watching the video, I thought if it were me I would be just as quiet as that INFP, because there just wasn't enough to engage my Ne; to spark my mind into gear and incite the desire to speak.
That's a good point. I think he alternated between wanting to speak yet finding no insertion point and "zoning out" (even though he was still listening) when it was clear that 1.) the extroverts dominated the floor and 2.) the stuff being discussed was insubstantial.
Even then, the things he expressed seemed to be more about showing empathy for and mirroring the others' tone, feelings and ideas, than expressing his own. It makes me think that I must come off like that a lot and that it would look like being railroaded or being shut off, when it's something else entirely.
Hmm yes, it is a "something else" - it looks from on the outside (as you say) being railroaded and shut-off, and that's a pressing point for me because what shows on the outside
is what most people are judging on. "The squeaky wheel always gets the grease" - certainly there are times when circumstances leverage better to our strengths, but that kind of situation can be problematic. If one was viewing the video without a lens to the inner space, you might think the guy was either stupid, ineffective or just had nothing original to say, or worse, was withholding to be contrary, almost mocking. By extension, it unfortunately shows how INFPs are sometimes not regarded as someone to take into account or make space for - like, there's no consequence to not making space for us. When the INFJ spoke, it wasn't that the extroverts were engaged by his words, they made space and relinquished the floor. The body language of each turned more submissive, less dominant. It was as though they didn't dare butt in lol! That did not happen when the INFP spoke, perhaps because he's "nice" and doesn't appear pissed when he's interrupted (not that the INFJ appeared that way either, but I sense history there). It would have required a much more concentrated burst of Ne in that situation to grab some time anyway and as you say, there wasn't much to ping off.
Anyway, just some thoughts. Learning how to create balance for ourselves as well as for others is an important skill. I can get so good at mediating I even forget what my opinion is and I really relish an opportunity to speak when the topic is interesting and I have something to say. I was a bit surprised the ENFP didn't try at least once to do that. Maybe the value is in seeing the dynamic play out like reality anyway.
eta: I guess how I think in these situations is that I'm listening to everyone else, giving them the courtesy of my attention, and then politely waiting reciprocally for my turn to speak. This assumes that the others talking understand that they are the recipient of that energy and have a self-awareness that everyone "should" be heard, has an opinion, even if it's only to express they don't have much of an opinion on the topic atm. So, when the people you're talking with don't recognize that, or are too self-absorbed to "get" that, it can be disappointing. When in a group, I try to pay attention to everyone, and some people assume this is because they must be rivettingly interesting, but no, it's because I value hearing everyone speak and can focus even if very bored. This can occasionally lead to misunderstandings too.
eta2: I seem to have a lot to say about this!