Question

Why does a frameshift mutation usually cause more defects during protein synthesis than a point mutation? apex?

Answer 1

I believe this is because the frameshift mutations can affect many amino acids. 
Frame shift mutation is produced by either insertion of deletion of one or more new bases. Since the reading frame begins at the start site, any mRNA produced from mutated DNA sequence will be read out of frame after the point of the insertion or deletion, thus producing a nonsense protein.

Answer 2

Frameshift mutations can cause many amino acids.