Most adhesives do have less strength in lateral shear. Heck most materials in fact are more prone to fail with shear forces - nothing new there.
Easier to break a stick by bending than pulling it apart. Perfectly normal for the most part.
I don't think any plastic repair product results in a stronger join than the original - not even ultrasonic welding can make that claim.
It's not even obvious that the shell cracks result from any kind of shear.
The advantage of CA and baking soda over a glue is that it will address voids, bridge gaps and is rigid when it cures - unlike plastic glues which depend on some degree of solvent action to create the bond.
So I'm not sure why the critique when shear strength may not even be applicable and a repair is certainly preferable to a fractured part.