He who mines the block can choose which txns to include and exclude. Everything is an attack on bitcoin if you ask the right person.

No one is entitled to block-space. Best we can do is economically incentivize block producers to sell us some block space for our txns. They are under no moral obligation to include any txn however 

 There is currently a discount rate for certain types of data, so this is only partially true. Enabling better spam filtering and making it harder for arbitrary data to outbid higher value transactions make Bitcoin better. 

 This may remove distortions in the free market for block space, but miners are under no obligation to include any one txn in the block they produce. They may be incentivized to, but not obligated 

 That’s correct.