Did a quick fact check, by that I mean I read 2 very long papers about finger bone stress. Although not the primary purpose, therizinosaurs did still use their claws for self defense with many species having claws that could withstand piercings and scratch-digging stresses placed on them. Ironically, not all species had claw shapes suited for this type of stress such as the name species therizinosaurus which scored the lowest performance all 3 tests. Studies from 2014 suggests an interpretation for stronger claws in therizinosaurs but these sentiments are not shared by the 2023 papers so it’s kind of up for debate right now, and I highly recommend read them if given a chance.

TL:DR He is partially correct but therizinosaurus doesn’t represent therizinosaurs as a whole.