in my area, they [junkmailers] actually interfere with delivery of mail, as a postie is not allowed to put anything in a mailbox that cant be closed [for privacy/security] so when the junk carrier shoves it full, your real mail cant be delivered.
[adndm] no posties cant [as in not allowed] remove anything, even if they just put it in there and realized its the wrong address
In the US, no one except actual USPS mail carriers are allowed to deliver anything into a mailbox. Everyone except the tiniest operations take that pretty seriously, since the US postal inspectors (mail cops) are extremely serious.
In the UK politicians also send out these kinds of flyers in bulk (never mind the inundation of flyers for takeaway food, Domino's Pizza, Papa John's, etc.)
For any single piece of legitimate mail (which is vanishingly small as most stuff is paperless now), there are perhaps 20 or 30 pieces of junk that come with it over the course of a few weeks.
I honestly wish it got legislated against. Junk mailers aren't entitled to offload their waste through my letterbox. I don't understand why they have the right to shove advertisements into my own home.