Many of the diseases are real, however the idea of a virus itself might not be how it actually spreads. The term "virus" predates the modern definition by over a century. If you study the source material for the current explanation for what the virus is, you cannot find verifiable proof.

Yes there are a lot of diseases, but the medical community doesn't actually know the actual mechanisms of many viral diseases. The concept of a coronavirus, if what they publish is anything like their source, is just idle speculation.