You have your opinion, many people with a great knowledge of metalurgy don't agree.
And many metalurgists agree with me. Or perhaps more accuratly I agree with the opinions of the engineers and metalurgists who disagree with those folks who think MIM is good for use in critical stress parts.
More importantly I used to be one of those people, like you, who that those MIM parts were good, until I had a critical part fail.
As I said, for a non-critical part like the front sight, go ahead and use MIM, or even plastic. But for a critical part then I'm no longer a kool-aid drinker like you. I had my bad experience, I'm just glad it was on a target range instead of in an actual gunfight.