Maybe Eyebreaker and many others don't know the lore that well. This should not be over seen. BG 3 is not only played by veterans... Therefore Lae'zel's babbling can be quite confusing if you don't have any background knowledge.
Illithids aka Mind Flayers are so psionically powerful that they simply don't care if you come at them with a Two-handed sword +20 or whatever, because they'll just stun and / or brain control you and turn you against your fellow players (watch from 16:07 min.):
That's the main reason we keep our equipment, because the Illithids simply don't care.
Beyond that, though, they probably figured you'd be fully restrained until the process of Ceremorphosis is completed....at which point you'd be no danger to them.
