What is your opinion on permissionless decentralized exchange for erc20
   tokens?

   Everyone can list any token in automized way.

   Everyone is responsible for his own funds and tokens that he/she lists
   and trades.
   It is p2p, permissionless, immutable, transparent, decentralized and
   semi anonymous.
   If you are interested try this one https://shitcoin.market.
   Write your comments in the troll box and let the shitstorm begin ;)