I can understand your response, but I would like to mention that I'm sharing a recipe that I enjoyed at a friend's house so I got the recipe from them and kept it around because it's a quick and easy thing to make.
Since you asked, No... I don't "always get ingredients out of a can and save the tinny tasting liquid..."
In fact, I usually give the liquid from a can to my cats because it's most likely a fish product.
Coconut milk IS one thing that I regularly buy in a can AND reserve the liquid from....
In any of these instances, I don't tend to notice any sort of tinny taste, sorry if you do.
However, I do occasionally eat with friends... friends generous enough to cook a meal for me with their limited, pathetic, meager cooking abilities. This recipe came from one of those experiences... and the funny thing was that I actually really liked the meal.
If you're offended by the canned foods, it's easy to switch it to being fresh bean sprouts & fresh or frozen shrimp... but I have not, to this day, been able to go into a grocery store and find fresh water chestnuts. So for them, yes... from a can, where else???
So then, what would you do to create the base for the sauce? Perhaps broth of some sort? Good... now where do the majority of people in our culture/day&age get broth? Don't most people these days buy it... IN A CAN??? and then RESERVE THE LIQUID???
I sometimes go through the trouble of making broth from scratch, and always really enjoy the results. I freeze a good deal and enjoy the results, but even I buy broth in a can.
If you don't want to try it, no one's forcing you to.
I tried it. I liked it. I liked it enough to occasionally make it in my home for my family and friends.
You are not at all required to do the same.
Guess I didn't enjoy your criticism today... I think it was the word "absurd" that kinda set me off.