This looks like a wire edm part for those fine interior features. My guess is the design on the thin cuts was optimized for that process - i.e. constant width cut except at the entry holes, which are drilled.

Where the "thicker" hexagon-ish zone is, they want stiffness. Essentially all the flexibility comes from where the sections adjacent to those which are thinnest. The resulting stiffness of the mechanism is controlled by the length of those thin sections.

The question of why "thin-thick-thin", vs "medium" the whole way on each side, may be because they needed some thickness for the adjustment screw to tap into. The opposite side would then become the same to preserve symmetry.

Whoever designed this had some aesthetic objectives too IMO. (i.e. looks cool)

This looks like a wire edm part for those fine interior features. My guess is the design on the thin cuts was optimized for that process - i.e. constant width cut except at the entry holes, which are drilled.

Where the "thicker" hexagon-ish zone is, it is essentially not flexible. Essentially all the flexibility comes from where the sections adjacent to those which are "thin". The resulting stiffness of the mechanism is controlled by the length of those thin sections.

The question of why "thin-thick-thin", vs "medium" the whole way on each side, may be because they needed some thickness for the adjustment screw to tap into. The opposite side would then become the same to preserve symmetry. There may be a vibrational consideration too as Solar Mike suggests.

I have a feeling whoever designed this had some aesthetic objectives too. (I.e. looks cool)

This looks like a wire edm part for those fine interior features. My guess is the design on the thin cuts was optimized for that process - i.e. constant width cut except at the entry holes, which are drilled.

Where the "thicker" hexagon-ish zone is, they want stiffness. Essentially all the flexibility comes from where the sections adjacent to those which are thinnest. The resulting stiffness of the mechanism is controlled by the length of those thin sections, most everything else follows from symmetry. The non-90-deg angles are somewhat arbitrary. Whoever designed this had some aesthetic objectives too IMO. (i.e. looks cool)

This looks like a wire edm part for those fine interior features. My guess is the design on the thin cuts was optimized for that process - i.e. constant width cut except at the entry holes, which are drilled.

Where the "thicker" hexagon-ish zone is, they want stiffness. Essentially all the flexibility comes from where the sections adjacent to those which are thinnest. The resulting stiffness of the mechanism is controlled by the length of those thin sections. 

The question of why "thin-thick-thin", vs "medium" the whole way on each side, may be because they needed some thickness for the adjustment screw to tap into. The opposite side would then become the same to preserve symmetry.

Whoever designed this had some aesthetic objectives too IMO. (i.e. looks cool)