The fallacy of coronavirus being a bioweapon

This myth has been cycling through the Internet: "Coronavirus was a biological weapon accidentally/purposefully released by ____ nation." Then, people from the government of X nation blame the government of the nation from which the report came for spreading lies. The problem is multifold-- this is a myth and it is being released like crazy across the Internet, usually supported by some unsupported statement that someone hypothesized irresponsibly to the media. These people probably did not originally make these crazy original statements without the knowledge or support of their respective governments, but the governments are now somehow responsible for the actions of all their citizens (especially those in authority positions) in the midst of this pandemic.

The coronavirus could not be a biological weapon for these reasons:

First and foremost, we do not have the technology to modify one virus into another working virus that is vastly different from the original. We are not smart enough. We can only make very minute changes to the existing DNA of organisms and even then we have to often hide these changes from the organism or the organism will kill itself. Although viruses are simpler than metabolizing organisms, they would still require God-like knowledge to modify in such a way that would create something that both worked as a virus and killed people the way we wanted it to. Biological warfare involves releasing organisms that already exist. We can take almost any bacteria and make it antibiotic resistant, but we can not change one bacteria into a different species of bacteria. At most, we could call our modifications a "sub-species", whatever scientific value that word has.

It would be stupid to make a virus for the purposes of warfare that selectively attacks and kills only the aged and dying portion of the country's population. If anything, that would help the attacking country because they would no longer have to support this portion of their population and that money could be directed toward war. It would also give the opposing country a great moral boost in favor of the war- "They killed grandma! Let's get them!"

The coronavirus is not deadly enough. A 4% mortality rate (and the actual rate is probably closer to 1%), would simply not put a dent in the population. The fact that even those who are sick usually do not have any or very mild symptoms means that the country releasing this weapon would not even slightly impair the country they were attacking with it. Anthrax, for comparison, when inhaled, kills 80% of those infected and causes nasty symptoms in those who don't die. It has long been and remains the gold standard for biological warfare for this reason.