OP: "This virus was natural therefore any investigations into its artificiality are moot."

Me: "This virus has unique qualities that made it especially contagious, so its artificiality is not moot."

You: "Other viruses in the past were also bad."

Me, now: Yes, other viruses in the past were also bad. If you meant that to relate to the previous comments I think you left out the important bits.

It's like if we were discussing whether we should investigate if someone caused a deadly landslide. Why would you argue that we shouldn't look into it simply because landslides also happen naturally? If there are empty crates of TNT on the top of the hill, shouldn't we look into it?