I never understood why we are limited in our amounts of liquids we can take aboard, but are allowed unlimited amounts of things such as chocolate. The argument that TSO present ("we donīt know what it is and it could be an explosive") would be pertinent to chocolate bars too.

Well, chocolate at room temperature is a solid. If they prohibited solids it would have
the unfortunate consequence of prohibiting clothes, paper
and ..well...people on board the plane. I'm sure they considered it, since
it would add an extra level of annoyance to our airport travel, but not it's not really feasible.