both of them suck. Had this been a completely full train, with no empty seats ANYWHERE, the "Karen" would've been 1000% in the wrong. And she absolutely should NOT have put her feet on a stranger. No. Never. Should not happen. It reminded me of a sibling tormenting another sibling on a long car ride or something.
BUT...
BOTH of them had an empty seat right next to them. And apparently there were empty seats in other parts of the train. The old lady wanted to put her feet up...why didn't she move over? She wasn't looking out the window or leaning on the side of the train or anything.
BUT...
The woman recording and posting the incident could've slid over too. Neither of them had more "right" to their seat than the other one did (and technically, Karen was there first, though that still doesn't give her the right to put her feet on a stranger). Furthermore, if the poster knew she was prone to getting upset easily, she could've at any point removed herself from the situation before she reached the point of a panic attack. Karen was remarkably calm throughout the ordeal...I wonder if she even realized she was doing wrong. At her age, could she have a touch of dementia?
So yeah...they both kinda suck, though Karen sucks much, much more. And Karen definitely should've been the one moved or--even better--escorted off the train. Had it been me, I would've moved; I don't care where I sit. Had I insisted on sitting in "my" seat and Karen insisted on putting her feet on me, I'm undecided if I would've started yelling "Help! This woman is attacking me!" or if I would've just yanked one or both of her shoes off and thrown them across the train. The temptation to shove a sharp object in her ankle (as suggested below <g>) would've been hard to resist.