“When did he denounce BLM?”
He didn’t need to denounce BLM or any other movement. He has, however, denounced violence of all kinds in protest.
BLM is not recognized as a domestic terrorist organization like the Proud Boys or the KKK are, per our own FBI, and your Antifa boogeyman doesn’t have a organized structure of any kind...so, by definition, isn’t an organization.
On the other hand, militant white supremacists are considered by federal law enforcement to be one of the gravest threats to national security, and your boy Donny refused to distance himself from them. Rick Santorum said it’s unfair for Trump to have to turn his back on his racist voter base.
https://www.vanityfair.com/news/2020/09/fbi-director-chris-wray-blew-up-trumps-anti-antifa-war-plan
(I cited a source but I know you’ll never read it because you want to maintain your narrow-minded, spoon-fed views.)