Are all these junk tokens a drag on Etherium Block Chain?

[HashFace]

We've all seen these junk ERC20 tokens being issued and airdropped, and if I understand correctly, they are smart contracts that operate on the Etherium block chain, basically sharing the chain with Ether.  I don't understand how this isn't the same as spamming the block chain.  Doesn't this slow down legitimate business, cause transfer prices to rise, etc?  What am I missing?