You can buy feminized or regular seeds from a seed bank.
Regular seeds are made through pollination of a female plant via a male plant.
Feminized seeds are made from female plants self-pollinating.
Regular seeds that have a chance of being either male or female do not necessarily have worse genetics. If you get a seed out of a bag of OG Kush from the dispensary then the seed still has the OG Kush genetics and is worth growing. Bagseed from good weed is going to be good weed if you are aware of the genetics, which in OP's case he can.
WHAT YOU seem to be referring to is shitty bagseed that you can get a dozen of in a single bag of mid or a few in someone's homegrown loud. Those seeds would be wildly different as you can't trace the genetics but you can with dispensary grown strains or pretty much in any legal state.
In short: If your bagseed comes from a reputable dispensary or breeder than grow that shit. If it comes from you don't know where then proceed with caution. Don't discourage people with good seeds from growing them just because you have a misunderstand of how the genetics would work in this scenario.