I get what you are saying, and I agree. And before I say what I am going to say, keep in mind I do am going to filter it.
But my line of thinking is this: They want to make money. If they made a bad quality product (contaminants, etc), someone would catch it with a test. The word would spread, and quickly they would start losing customers. Thats why I believe they do make an effort to make a high quality product. Not because they care about "us", because they care about them.
This is the problem with testing as "harm reduction".
The type of testing we rely on is primarily for identifying its the correct substance, quantity, and a rough measure of its purity,
It's the "purity" part that gives people a false sense of security, because its meaning in chemistry terms is not how most people interpret "purity".
If I tell you a bottle of water has been tested and is 99.9999%. pure, you'll know it's free of dangerous contaminants and safe to drink.
If I tell you that peptide is 99.8% pure most assume that means it's also free of contaminants and safe to inject.
Except that's not what it means. It's not a measure of "other stuff". The only impurities tested for are other things closely related to the peptide. Pieces of it, the wrong sequence of proteins.... essentially defective peptide.
You could have a dose of arsenic, some mold, and ground up dried worm in the vial and still have it test 99.8% pure. All those other things require separate tests. You have to be looking for specific things to find them.
I'll also point out that all samples are filtered with a .22um syringe filter first. That's standard practice.
So the test results are of the reconstituted peptide after it's FILTERED.
If you're not filtering, you're not injecting what the test results show.
The only harm you're protected from by the tests is 1) The harm of getting ripped off and 2) Getting the wrong substance, which could be harmful if you get something like Melanotan instead of Reta.
Pharma does "purity" testing, but it's only one 5 to 8 different tests on each batch of peptide to ensure safety.