It's quite accurate actually.
Many popular protein supplements are full of fillers, heavy metals and have very poor amounts of protein.
If you have a good diet than Omega 3 supplements could just be a waste of money even IF the quality is high.
If you're diet is crap and you're activity is so over the top extreme than maybe an electrolyte formula might not be just really expensive urine?
Your original claim is that pretty much all supplements are "scams" and their claims are "cons". That blanket statement is false. I'm sure some are, but not "pretty much all". There are high quality and poor quality supplements.
There are high quality trainers and poor quality trainers, we don't assume all trainer's claims are scams or cons do we?
Omega 3 supplements can have positive benefits regardless of diet. Many people have a genetic predisposition to poor lipids profiles.
Electrolyte supplements are used pretty widely by all types of athletes. A person does not have to have a 'crap' diet coupled with 'extreme' activity level to realize some benefit with them.