Although I too hate spam, I am not sure blocking users is the way to go.  I agree that Steemit was built on full transparency and non-censorship because all postings are forever "available" on the blockchain.  But, there is still a great deal of censorship taking place on the visible layer.  

Flagging is just one such vehicle.  Although it does not completely remove a user or their post from the visible layer and certainly doesn't from the blockchain itself, it does put them in a state, if enough flags are received to make it less obvious they are there to most users.  I do consider that censorship.  

The biggest type of censorship is censorship via bullying.  I see that all the time on steemit.  I would say that 90% of the time I agree with what is happening but again, it is censorship.  

I am not sure there can be a truly top layer censor-free steemit.  I am not sure what that would look like.  I do understand that whatever is written is on the blockchain and will be on the record forever but how many people do you know that are going out looking at the individual records for each post ever made.  Very few.  

I wish there was someone more akin to Basic Attention Token (BAT), where I can setup my settings to allow for spam and other types of advertisements based on a certain reward that I would receive from the publishers of such spam and advertisements.  Publishers pay for my attention to their content.  I think that is a more effective way to deal with it.  Anyway, just my thoughts.