1.- Wow...I can tell you haven't had much experience with NTFS, have you? Protip...it really isn't hard to corrupt the MFT and index on NTFS, especially if you don't do a SFC before doing major operations...wanna guess what Windows 10 did NOT do before upgrading?
2.- Damaged their computers? I can assure you that is a YES because if you computer is rendered unusable, as were many PCs that were caught in the endless reboot bug? Then it might as well be bricked for all Joe and Sally Average are gonna be able to do about it. Oh and lets not forget MSFT forced driver upgrades and both AMD and Nvidia have had driver releases in the past year that could damage hardware, if MSFT forced those drivers on to her system? yeah it could cook hardware.
3.- Damaged her hard drive? See #1. MSFT frankly made the most piss poor upgrade compatibility checker I have EVAR seen with Win 10, in fact I had several systems at the shop where their upgrade checker said "Oh sure its totally compatible!" only to find MSFT's idea of "compatible" meant no graphics, no sound, and no networking. If she had damaged sectors on her drive Windows 10 wouldn't bother to even run SFC or even check SMART before slamming the drive so yeah it could easily kill it.
4.- Having to replace her PC? Well there is the fact MSFT hasn't forced OEMs to provide discs since WinXP which means she had no media to install from even if she had the skill to do a HDD replacement (most wouldn't have a clue how to) and if the only repair shop in her area was something like Geek Squad? Well the cost of a HDD replacement and OS install would probably cost her more than the system was worth, if hers is anything like the local GS she'd be looking at over $200.
So I'm sorry but everything listed checks, and moreover I can back up her claims as I too had several systems lose files because of Win 10 not bothering to do any checks before upgrading (oh and in the case of 2 boxes never even asking me before they started upgrading as they were 2 of them affected by MSFT changing the red X from meaning no to meaning yes) and lucky for me they were just shop boxes and didn't have any files I gave a shit about but with their shitty upgrade installer? I could have easily lost crucial documents or pictures so I really do not doubt she got screwed by Win 10, its Vista levels of bad.