Remember back during the impeachment trial, Pelosi rushed the impeachment through the House as fast as she could. You see, she expected there to be a month long process of calling witnesses. However, after the house passed the impeachment article, the Senate told Nancy they would not be calling witnesses. The Senate told Nancy they would base their decision on the evidence contained in the articles.
So what happened next is Pelosi held on to the impeachment articles for an entire month after rushing them through the house. People were confused why she would rush the articles through the house and then sit on them for a entire month. Let me tell you.
One month later the first covid patient arrived here from China and on that day Nancy handed the articles to the Senate. With the Senate refusing to bring in witnesses, it messed up Nancy's timing. She was exposed. They hoped to distract the POTUS with the impeachment while the Covid took off. Look over here, not over there.
Throw in the fact that the democrats would later use covid to run fake attack ads blaming Trump for the deaths. Add in the damage to the economy and unemployment rate. Add in the universal ballots, Add in the social distancing to prevent poll watchers getting a close look at the fake ballots.
Yes, it was coordinated attack on our society. Accomplices include WHO, China, Gates, Obama, Fauci, Burkes, Redfeild, Cuomo, Newsome and many others. It is called crimes against humanity and they should all receive the death penalty.
In my opinion, the reasons would be to fine tune death rate and certain properties. They need something that spreads well, is somewhat abnormal and doesn't cause too much death, while also able to be a timed release.
So they're more interested in a bioweapon for a bioterror propaganda campaign, explicitly not wanting something too strong.
That's just the reasons I could see as to why they might engineer something. Doesn't mean it's what happened, but you asked why they might and I answered why I could think they might.