Can only agree.
Normally one wants the self oscillation frequency to be as high as possible.
As otherwise the wing will suddenly start to do "odd" things and wobble and maybe break
Have experienced this with model sailplanes, when going past 200km/h and the resonance is hit, a carbon wing simply explodes to "smitherines" - a view that would please the Mythbuster group to watch I am sure
There are two ways of increasing the resonance:
Weight - keep the weight as low as possible.
Also, the distibution of mass is important, actually more important than the absolute mass.
This is in order to keep the moment of inertia down - which raises the oscillation frequency.
The mass (moment of inertia) should be as low as possible just at the C.O.E (Center Of Effort = where all forces act if hang up in a string)
And the second way, is to increase stiffness.
These two properties are a bit counterwise, meaning, you can design a very very light and good weight distribution wing, which is not that stiff, just "adequate" - and it will work without oscillations.
This is what we often do in the aircraft design, as we get a win-win then.
Especially, as IF a high frequency oscillation starts - then it can be easier recovered, in particulary with low mass - instead of ending in a catastrophe...
The other method, is to increase stiffness A LOT, often on cost of weight (and price/materials/production methods).
This gives another benefit - namely that our hydrofoils are stronger during handling (riding into something, rolling over a sandbank, etc etc)
I can show you a photo of the design principles in aircraft later, as it is really amazing how efficient a carefully balanced light weight design can work much better, than one based on pure "strength"
PS: There can be oscillations both in regards of