If you know the contract address you can trade any token.
You're right but the problem is they are not listing any new tokens. And while one can trade by knowing contract address, it definitely gives the project a proper identity after getting a ticker and name listed on an exchange.
The community and users also feel much more comfortable while trading since the token is already listed on the exchange.
Nevertheless, I congratulate you in your initiative to improve crypto world.
A new DEX is always welcome for the community.
Thank you.