Here's an unpopular opinion. Firefly was a terrible show and was rightfully cancelled. Not sure why it is so revered amongst neckbeards. It's a poor rip off of Cowboy Bebop.
Popular or unpopular, you know why you've taken a hit? Because you offer no rationale whatsoever for your opinion.
Bad acting
Over used tropes
Unimaginative plots
The entire show was a poorly executed "train job".
I agree with it totally having elements of Cowboy Bebop. Who couldn't see that right? It is interesting how this is the first comment on this HN post to mention that. Though Cowboy Bebop was huge in anime, I think many who watched and loved Firefly have not seen it. My anecdote - My wife enjoyed Firefly but has never seen Cowboy Bebop.
You're claiming that the show is a ripoff of an anime, and you don't understand why it has nerdy fans? I don't accept your prior, but it does provide a clear answer to the question with which you have trouble.
The show is a poorly executed weeaboo fanficton gone wrong. Sorry you're all mad.
I'm not mad, I'm confused. Even by your own lights you don't seem to be making much sense. Are you sure you've thought your opinion on this all the way through?