Since the 5th row is perfectly comfortable, the OPer can avoid future standoffs by simply choosing the 5th row from the get go.
Seriously, I think the thread title accurately sums up the OP’s position. I wish she’d have just couched her true feelings into a rant, instead of pretending to solicit feedback. I also wish she hadn’t padded the OP with filler, which she’s obviously concocted to bolster her unyielding stance.
For instance, I simply don’t believe that the patrons on either side of them were sniffling, and THAT’s the main reason they didn’t want to move. The whole “I wanted to spare the sick girl’s feelings” is as ridiculous as it was fictitious.*
Furthermore, I don’t believe that the movie was already 3-5 minutes in progress when the latecomers first asked to be accommodated. If it was, that would have been, and should have been, the OPer’s loudest complaint. And I believe that anyone sitting around her would have backed her up, by shushing the latecomers, or shouting at them to “Sit down!!”
Finally, as others of said, I mean, as others HAVE said, “So who do you think was in the wrong?” was disingenuous. Her opinion, in all its glory, is right here: “But to me, I don’t need a reason. If I didn’t want to, I didn’t want to. It’s as simple as that.”
FWIW, I concede that the OPer has a point, even stripped of all the added baloney.
*P.S. For future reference, a more effective thing to say might be, “Sit here if you want, but I just got over the flu.”