There is not a low fee security problem. 

The systems is elegantly Responsively Resistant. Waiting for an *attack* 

Fees will spike in response to degens/spammers/scammers AND TO *attacks* from those censoring transactions. The sudden lucrative fees incentivize more mining.

The attackers *mostly* have to pay in miners in SATS and they know this. Gets too costly. *attackers* run out of resources. Fees fall back to baseline.

Like the toughest kid in the schoolyard. Rarely has to fight.

Or a massive militarized border that never fires a shot.