Second question: Is LocalMonero a mixer/tumbler for XMR coins? If your answer is "yes", I assume that AgoraDesk is also a mixer/tumber for BTC coins?
No. First, those kind of platform is not a mixer or tumbler. Second, Monero did not require a mixer or any similar platform as such.
Both LocalMonero and AgoraDesk establish their website clearly as P2P platform. You can see it on their respective About page. Regarding Monero, the underlying technologies are inherently private. It developed and implemented to ensure users privacy and security in mind.