It's definitely overstating things. Bad dumps are possible and were somewhat common back in the day when people were spreading ROMs via GeoCities pages and Usen

It's definitely overstating things. Bad dumps are possible and were somewhat common back in the day when people were spreading ROMs via GeoCities pages and Usenet, but these days databases like No-Intro and Redump have helped make sure that they're rare - you can easily verify your ROMs against known good ones.