You are correct in thinking that seeds reduce AA production, but seeds can grow ever without pollination. [Growers try very hard to avoid this, since commercial brewers pay for AA, not weight] As far as getting leafs, etc. in the hops. Most hops are mechanically harvested these days and an occasional leaf happens. If you've never seen Magnum, you are in for a surprise. It is normal for the flowers to have leaves in them.
The final solution is to grow your own.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk