Honeslty, what version of Trek are these people watching that isn't obviously leftest? TNG and DS9 are pretty left leaning IMO. Perhaps you could argue VOY and ENT are less so. I think they're less outwardly political at least.

I was watching a video early today and they pointed out that the Simpsons have become empty signifiers. Their original subserviness has been hollowed out and they basically represent whatever people want them to represent. They're such a big part of the cultural Zeitgeist that they can mean anything to anyone.

I suppose one could argue that's the case for Star Trek, especially if we take into account some of the more modern bastardisations of the brand.

Then again, another part of me wants to chalk this up to people being dumb. If you listen to RATM and think they're anything but radically left, anti-establishment and anti-authoritarian, it's not the product of the greater cultural forces of late capitalism. It's cuz your dumb.