Officially, there are no transaction fees in Steem.
Instead, the witnesses are paid out of inflation which is new currency creation.
This means that everyone pays transaction fees via dilution of their stake.
It is like collectivism, where everyone pay the cost of actions of some.
The spammers can freely send their 0.001 STEEM/SBD messages, payments to bidbots, and other payments and the passive users participate in the cost.
Such policy damages a blockchain by requiring more blocks due to more transactions and slows the flow in real time.
Both time performance and space performance were already permanently damaged, unless a hard fork will be done, and it will not be done, assuming my perception of the witnesses.
If spammers had to pay for each transaction, there would have been far less advertisements via memos in 0.001 STEEM/SBD transactions, less of the smaller bidbots, less resteem "services" and less shit content.
Again, decentralization and freedom of expression mean freedom of plagiarism and no copyrights.
In freedom there are no rights, and enforcement of a right contradicts freedom.
More generally, I prefer each one to pay for each of one's actions.
With no subsidy by inflation which makes the cost collectivized.
edit: I just found my nostalgic comment here when I searched for something else:
https://steemit.com/steem/@lexiconical/steem-usd1-07-plumbing-the-depths-of-usd1-support-at-bittrex-today#@stimialiti/re-lexiconical-re-stimialiti-re-lexiconical-re-stimialiti-re-lexiconical-re-stimialiti-re-lexiconical-steem-usd1-07-plumbing-the-depths-of-usd1-support-at-bittrex-today-20170820t035022232z