My opinion is not worthless.
We all have opinions, and just because you have “credentials” does not mean your opinion is any better than mine.
It is a free country and we are free to have opinions.
Well, I wish it still were a free country, but that is beside the point.
you are correct that you have a right to your opinion. I would never argue otherwise.
I’m sure that my opinion is not better than yours in many, many areas, and may in fact be worse.
But on this particular subject, about which I have a lot of experience and expertise, my opinion remains that your opinion worthless.