Yes, a missile defense plan for the Czech Republic is a good idea, because a missile defense system is a good and economical way for a country to have a defense system. It is much more cost effective than a standing army, and there is not as much of a risk of loss of life.
It is the right of every country to be able to defend themselves against the threat of an attack. The Czech Republic's missile defense system is designed to protect them from attack from other countries. It may not be a good idea to proliferate missiles, but if a threat exists they should be able to protect themselves.