From a more philosophical point of view - expecting a large corporation to go mano a mano on your behalf, against a major state security organization...that's right up there with expecting Santa Claus to punish all the evil spies for being naughty.
First, I haven't seen any indictments of any BLM rioters. Note when I say rioters I'm not including protesters but those who set fires and harmed people.
Second, while I'm against contact tracing apps in general for the reason they can be abused, I don't think they would be needed by LE given their ability to setup string rays, drones, and monitor social media.
Most of the BLM rioters and Antifa terrorists are known. Raz Simone is still free although he setup CHAZ, passed out rifles, and extorted public officials with political demands while claiming public land allowing 6 people to be killed under his "security".
- https://www.zdnet.com/article/singapore-police-had-used-covi...
- https://slate.com/technology/2020/06/contact-tracing-law-enf...
Given the past decade (Snowden & Assange) I don't find strange contact tracing being used for "other purposes". The data is readily available so, why bother with drones?