The top drawing shows the correct way with the igniters wired parallel.
Think of it as all the igniers are wired basically the same and have a seperate connection to the plus and minus.
The second drawing (The wrong way) shows the igniters wired in series.
Think of it like some Christmas lights. Look at the circuit. Once one igniter goes off and the circuit breaks none of the remaining igniter get any power 'cause the circuit is now broken.
Like if one Christmas light goes out...they all go out!
To complete the explaination, on the parallel circuit, when one igniter burns out, there is still power to the remaining ones (that was implied in your description, but I figured it couldn't hurt to say it )