You're talking about US death certificates, I assume. It's the norm to list more than one thing that lead to death: e.g.

Heart failure - Lung failure - Trauma - Automobile crash

So for covid-19

Respiratory failure - diabetes - COVID-19

You're saying that Respiratory failure or diabetes is the 'real cause of death', but COVID-19 is actually the cause of death. This has been common practice for years, stop believing what Mc. Nixon tweets out.