First off, any make and model of handgun belongs in a holster while carried. Period. No exceptions. (Holster, fanny pack, belly band, dedicated holster/purse, etc. You get the idea.)
Glocks are no more dangerous than any other handgun so long as the 4 rules are followed. Fail to follow those, and the carrier is dangerous, not the Glock.
That said, modern handguns, Glocks included, should be carried with a round in the chamber. Folks uncomfortable with that who carry are in need of more training and familiarization with their weapons, imo.