> The reality is, for things like video and pictures it probably won't be a problem. However, if the data is sensitive, you should be using a raid 6 with 2 disk redundancy, coupled with constant data scrubbing to ensure that the disks remain bit rot free. The probability of bit rot occurring at the same place is probably less than 1 in 10^16, possibly even less if data scrubbing is constant.
The first assertion is simply wrong: the internet is littered with people who have corrupt media files which cause user-visible errors. Beyond that, however, RAID can be part of a strategy but is far from sufficient. The paper you linked provides a good discussion of the reasons why but the root mistake is assuming that failures are perfectly distributed random events at a single point.
End-to-end strong integrity checks are so important because e.g. in that scenario with a two-drive RAID array you'd still be subject to errors caused transferring the data from the host to the RAID controller, on the controller itself, in communication to the drives (one reason why it's important to mix vendors & models), and on the path back when reading data. You'd also have to worry about corruption in memory, errors caused by e.g. power fluctuation or other hardware events which may be grossly underestimated because they're silently detected and retried until you get lucky and one of the 100,000 errors happened to generate a valid checksum, etc.
Generating a cryptographic hash as early as possible and checking it at every stage is key both because it catches almost all of those scenarios but also because it allows you to confidently report a positive validation result rather than just the absence of detected errors.