I've never had a problem with bugs being attracted to starch. I don't see why they would be a problem unless someone is storing starched fabric for a long period of time, perhaps in a humid climate. I usually make quilts that will be washed rather than wall hangings, so perhaps that makes a difference.
I have tried both spray starch and sizing; they do not stiffen the fabric sufficiently for me. Maybe it's just me, but I also hate the overspray problem with sprays. With spray starch I always seem to scorch the starch too!
However, the biggest difference between my method and the sprays is the degree of stiffness.