Why was it ridiculous for the US to accuse China of stealing its vaccination research materials?

If you have a good basic understanding of how things work, you will know who is lying or smearing.  Therefore, I will explain briefly the vaccination researches adopted in the US and China.

The US pharmaceutical companies are using the mRNA method (new) to produce their covid vaccinations while China is using the tried and tested method (traditional) of using an inactive virus to produce its vaccinations.

In layman's terms, the mRNA process is to retain some parts of the genome that won't change and remove the parts that will change from the genome.  Therefore, the incomplete virus with consistent parts will make the body recognize the "virus" and trigger the immunity to kick in.  Since the modified RNA strain is not a complete virus, it cannot harm the body like a complete virus does.

The traditional method of using an inactive virus works in a completely different way.  The process is to inactivate a virus by preventing its replication process or blocking it from latching itself to DNA.  In other words, the inactive virus becomes incompetent and cannot replicate itself in a body because the transmission process is blocked.  Therefore, this inactive virus will make the body recognize the virus and trigger the immunity to kick in but it will not harm the body since it cannot replicate itself in the body.

Since the US and China use different approaches to produce their vaccines, it doesn't make sense for China to steal US vaccination research materials as China cannot use such irrelevant materials to improve its vaccines.  There is also no need for China to steal the US vaccination's data because the US has to reveal the efficacy rate, side effects, and immunity period for usages.