Probably another point is that the encryption for Matrix/Element has undergone multiple audits, one in 2016 and another one of their newer rust library. Whereas telegram just has not. There was this also a not too long ago. MTProto is also used nowhere else, whereas a lot of encryption has been influenced by the Double Ratchet which is well understood.
The other thing worth noting is that Matrix is the foundation for other products which many governments use for secure communications.
It's probably also media's fault for this. They only publish when a bad person does a bad thing on the internet with it, not all the millions of users who don't do bad things. That would be boring.