It's not just security, but the use of influencers and bots to defame other brands as well as multiple documented cases of industrial espionage. The worst thing is Xiaomi uses these influencers to create a "Jai Hind"-like cult of personality around Xiaomi and Lei Jun so that Xiaomi fans believe Xiaomi is always being victimized. Xiaomi also uses its influencers and botnet to mass report posts to limit their visibility, or in some cases, get them taken down.
For reference, the cult-like behavior is so extreme that Xiaomi influencers were caught recruiting minors to defame competitors. Multiple Xiaomi influencers directly affiliated with the highest levels of management have been arrested for violating the law. One escaped to Italy.
Xiaomi constantly boasts about their self-developed technologies, but they largely license, or in some cases, outright steal, technology from other companies. I would caution against taking anything written about Xiaomi on social media at face value, especially after this incident. Xiaomi's internet army was able to suppress news of the accident for 2 whole days before the authorities stepped in.
Some high-profile members of this forum use posts from Xiaomi influencers as news. I hope this is done out of ignorance, and not malice. While Xiaomi has made contributions to science and technology, we should seek truth from facts and not be tricked by their false marketing.
So what technology they stole from which companies?