Definitely an interesting discussion, thanks @cagince!
Overall I think you make a very strong point. However, we do need to keep in mind that the tokenholders are the ones in charge of setting adequate risk parameters, and should take idiosyncratic risks into consideration.
The question is, as you stated, what if you want to provide insurance for one asset, but not another? Perhaps we can learn something from the folks over at Nexus Mutual. Worth investigating.