They're obviously not "junk". I was a 2111 in the Marine Corps (small arms repair, hence my FR name). The simplicity and ruggedness of the Mosin design is in my opinion quite an engineering accomplishment.
The Mosin I own is quite accurate. You obviously don't own one or you wouldn't be making such ridiculous statements.
I own several Mosin-Nagants, including M91s, 91/30s, M38s, M44s, M59s and a Finn M39 plus a repro 91/30 sniper and an SVT40. So much for your assumption of the “obvious”. They can be quite accurate, but the action is hopeless. Are you aware the Finnish sniper you refer to only used iron sights?